Premise:
- 64MB blocks are allowed
- 64MB blocks take over 10 minutes to verify
Question:
What financial incentive exists for a miner to produce such a block?
Am very glad you asked this question.
Let's say you are a rich corporation with money to waste on the most expensive mining rigs, supporting computers and the best bandwidth available on the planet.
You now expend all of those resources to fill up your blocks with 64 MB of txs (create your own txs if you can't find enough from others in the mempool) which basically no-one else can do (and will struggle to even verify in 10 minutes).
You now *own* the blockchain and get all the fees and block rewards - of course that means that Bitcoin is no longer decentralised but of course you'd try and pretend that you were more than one identity wouldn't you.

The people that think getting Bitcoin to compete with the likes of VISA is just a question of increasing block size are naive at best (or at worst are actually being paid by whoever is wanting to gain control).