It's very strange for you to argue that executives pay mostly income tax. From the perspective of a corporation, their main concern is paying corporate tax. The people who own the shares then make gains from capital gains.

Uber is a growth company, so we can expect that corporate tax has little effect on them, for the simple reason that they're not making much money (by design). Still, their capitalization has some notion of corporate tax baked into it, because if they become a giant and start returning earnings to owners, then this will be impacted by corporate tax.

I don't like that we have this complicated system of double-taxing corporate earnings at lower rates, as opposed to taxing earnings as income for the owners of the company. I know that many companies find ways to skirt corporate tax... but not all, and not really the majority (but preferentially the huge companies). I also know that the combination of these two taxes may not total to what the individual owners would have otherwise paid if the earnings had been ordinary income. Still... it's not as simple as "capital gains".

"...many companies find ways to skirt corporate tax... but not all, and not really the majority (but preferentially the huge companies)"

So that's basically the case for progressive corporate tax. Everyone acknowledges that small/medium business pay the full tax rate, while large/huge corps always never anything close to it. With progressive taxation you can directly impact the latter and not the former.

Why tax productivity at all? A land value tax redistributes gains in productivity to the government in the form of tax levied on the value of land - the value of the improvements on the land.