You say that as if you never bought a raspberry pi because it lets you use Mathematica. There's many of us who did, because a pi is <$100 and a home use license for Mathematica is $300+

If you need a pi because you want to run something on it that'll run just as well on a pi 2, then sure 2GB is perfectly fine. But if you actually need a pi 4, you need it because it is vastly more powerful and offers actually useful amounts of memory.