Nah. Those California devs are running MacBooks like me. Most of the new ones only have 8GB of ram, but macOS is a bit weird. I’d say 8 on Mac is about like 16 on a PC.
My intel MacBook has 16 and it runs the jetbrains suite pretty well, but I haven’t messed with RustRover much. It being EAP may mean a debug build though, so not as optimized.
Don’t forget if you did a year sub, you get a perpetual fallback license to whatever version was current on the day you subbed. So even after it’s over, you can still use CLion.