Harvey building TaxAI is very interesting. They seem to be expanding to other services https://www.harvey.ai/blog/harvey-co-builds-custom-model-for-tax-with-pwc

The most likely driver of actual tax reform that I can see is not legislation.

It’s open source E2EE software you run locally that does everything for you with precision and maximum deductions based on prompts it gives you. 

Seems technically feasible but there would be heavy lobbying to make this illegal.

If you’re PWC I get why the focus is on assisting tax professionals but regulatory capture is the only reason it would stop there. Why would the UX not just get so good you can use it as a complete layperson