An upgraded Studio will be about the price of a base PowerMac G4 ($1700 in 2000 is about $2900 now adjusting for inflation). The Studio that is this price has the M1 Max with 10-core CPU, 32-core GPU, and 16-core Neural Engine. It also has 64 GB of RAM and a 1 TB SSD (or you could stick with 32 GB RAM and get a 2 TB drive).I've had no interest in Mac pros since the days of the powermac G4/G5. they priced them selves out of reach after that. iMacs became a much better value. now they screwed up the iMac and I don't even know what to buy.
It's not upgradable though but Macs haven't really been particularly upgradable for a long time (and Jobs never really wanted them to be upgradable so this is nothing new).