That's not accounting for inflation - $5000 then was more like $10000 now. And a bare-bones minimum machine for running business software (i.e. no color graphics or floating point hardware) was still close to $2000 (more like $4000 in today's dollars). So, roughly speaking a maxed-out gaming rig today is about as affordable as a bare-minimum box in 1990, without even accounting for the massive difference in absolute power.