First of all, because the scaling is not infinite. There is a finite amount of potential users of bitcoin. Even if this finite amount is big, and is reached, the resource problem is not RIDICULOUSLY large. Satoshi pointed out in 2008, that one can expect, IF EVER BITCOIN IS GOING TO BE A WORLD CURRENCY, to have about 1 GB blocks.
How are you supposed to keep the bitcoin network decentralized if we are having 1GB blocks every 10 minutes? who is the custodial of the network if not a couple of deep pocket corporations and how is that decentralized at that point?