Its by no means certain that ICEs will get sufficient investment to improve as much as you say. Dieselgate, carbon taxes and outright bans in much of the developed byworld, China and India choked with pollution make it a risky proposition.
Even if ICE efficiency can improve substantially, can it match the rate at which the price of batteries is falling? Morgan Stanley predicts EVs will reach price parity with ICE in 2025 and then continue to get cheaper.
https://insideevs.com/morgan-stanley-evs-price-parity-ice-20...
Add to that cheaper fuel and maintenance. I think you are being too optimistic about ICE's future.