When the Raspberry Pi 4 came out almost two years ago, it came in four “Flavors:” 1GB, 2GB, 4GB and 8GB with prices being $35 for the 1GB unit, $45 for the 2GB unit, $65 for the 4GB unit and $75 for the 4GB unit. Things under this scheme went well for a while, though sales from what I heard were not perfect. The R-Pi 4 2GB and 4GB units sold the most, while the 8GB and 1GB units sold the least. So in their state of business mind, the R-Pi 1GB was taken off their product line.
 
More than six months later, there were many complaints about the R-Pi 4 series being too expensive and too powerful for basic robotics projects. Why some did not go back to the R-Pi 3/3+B or 3+A is beyond me. Some excuses I heard stem from the current Raspbian OS being 64Bit to robots needing to make quick second decisions and the R-Pi 3 was not fast enough (a load of crock if you ask me!). Thus the Raspberry Pi Foundation brought back the R-Pi 4 – 1GB series.
 
(Personal insight)
 
One of the biggest pet peeves of the R-Pi 4 I hear is that despite its speed, it is one of the hottest running units out there. Current units start at about 1.2GHz, it can be taken to 3.0MHz. Older R-Pi 4 units start at about 1GHz and up to 2.0GHz, though it can be taken down to 900MHz (this is not possible with the newer R-Pi 4s). Running over 1GHz on any system, the CPU will run hot and a heat sink is needed, yet the R-Pi 4 units are sold without a basic heat sink. Also, the faster you run the CPU, especially in battery operated systems such as robotics and environmental monitoring stations, the more power they use and the faster the battery will run out if there is no form recharging the battery.
 
Running with this, the R-Pi 4 system does not have a shut down protection when it over heats. Many Intel and other CPUs, or the systems they are built upon, when they sense that the CPU is in thermal run-away from having lost their cooling protection, the system would shut down until the situation has been rectified. With the R-Pi units, the system continues to run under thermal run-away until they simply burn out. This despite the ARM processor used on all systems since the late 1980s had a built-in thermometer which can be used to measure the CPU’s core temperature through an internal or external program and act accordingly when things got too hot.  
 
Note: Due to the running of the CPUs at or over 1GHz, the CPU runs hot; this is a handicap when in use for the Astro Pi unit. The Astro Pi uses the original R-Pi Model B+ (aka R-Pi B+) running at 700MHz with the Sense Hat, a 5mp Camera and a few buttons wired in enclosed in an aluminum case and has no heating problem. There are several in the ISS for schools and school to run various experiments in space provided that they have a couple of Astro Pi Units in the school to compare data with the one in space compared to the one on Earth in school. Many of these Earth-bound Astro Pi Units are 3D Printed and have a plastic non-working heat sink on the bottom of the case. One can order an Astro Pi in the aluminum case but few schools have $500 to buy 1 Space Flight Approved Astro Pi when a much cheaper 3D printed unit can used as part of being in the program.
 
If you want to 3D Print build an R-Pi case, you can get the files and assembly instructions here:
https://projects.raspberrypi.org/en/projects/astro-pi-flight-case
 
As I (and a few others) discovered and noted to the Raspberry Pi foundation, if one uses an R-Pi 2 or higher unit, due to that they can run at 1GHz or faster (the R-Pi 2 runs at 900MHz but can be easily over clocked by the OS), the temperature sensor on the Sense Hat begins to read the internal temperature of the Astro Pi case as its temperature rises and not the external temperature is it supposed to read. It turns out as they (the Raspberry Pi Foundation) admit that this is a design bug in the Astro Pi Case design. This is not a problem if one uses an original R-Pi Model B+ as they run cold while chugging alone at 700MHz but is a problem is any other system is used in it
 
Also, with the USB and Ethernet Ports placement redesign, an R-Pi 4 unit will never fit into an Astro Pi case. Some have modified the Astro Pi case to fit an R-Pi 4, but they run in to the same problem of the internals of the case heating and the temperature sensor measuring the internal and not the external of the case.  But again, the price of the R-Pi 4, despite its larger RAM size, is not wanted into an Astro Pi project due to its cost. Thus the 1GB version of the R-Pi 4 is wanted for this project. (WHY?!! The more RAM in the system the more data one can collect and larger science programs can be created to collect that data. Somehow the logic to this does not make sense in wanting a smaller RAM sized unit when a unit with more RAM would be more beneficial to such projects.)
 
[Conclusion?]
 
Thus for whatever reason, the Raspberry Pi Foundation released the R-Pi 4 1GB unit. Though I can see where it can be used in various systems and set ups, there is an odd sense of wanting it within the Raspberry Pi community. There is also an argument about how much RAM a system must in order to be a viable system, where the raspberry Pi Foundation is claiming that a system should have 2GB or more for it to be a viable system. Wow. What about all those schools that are using the R-Pi Zero from years ago with 512MB of RAM or going back further, schools using the older Model B/B+ and Model A/A+ with 256MB (with the Model A/A+) and 512MB (with the Model B/B+)? They were viable systems back then and still are today. And the Astro Pies used in space are using R-Pi Model B+s and recommend the Model B+ for Earth Bound Astro Pies.
 
It is great to see the R-Pi 4 – 1GB unit being returned to the market but I think it is being returned for the wrong reasons. For the past year and an half, there have been rumors of an R-Pi 4A model to be released but one never has. Such a 4A model would have half the RAM of 4B systems with 1 or 2 USB ports and no Ethernet while on a smaller sized board. The R-Pi 4-1GB unit is more like an R-Pi 4A system, and since the 4A unit is not being released (as of the time of this writing), I believe that this R-Pi 4-1GB is the Model 4A but with full ports.