Your delusional if you think GPU and ASIC mining is comparable. ANYONE can buy a gpu and fire up a rig. yeah maybe the big boys could get thier GPUs from the source maybe 50% cheaper than the regular joe but at least everyone has a shot.
That's not true. In a GPU only world those with facilities near to negligible cost power can still push the difficulty so high that 'normal' people are to mine at a loss even using the same hardware. The GPU generation was also rather maintenance heavy and so centralisation again helps with that.