We won't be back at square one even if the fees end up the same, since the transaction thoroughput would be higher.

Bigger blocks means more transactions per block and at a constant rate of 6 blocks/hr that means the network can handle more TPS before fees rise. As long as the mempool remains relatively empty, fees will be low.

By that argument, we should have capped Internet bandwidth at 56kbps.

Imagine if they increased the block size and developed Lightning in parallel. On-chain fees would be low until Lightning becomes mainstream then Lightning fees would be even lower.