apple's situation itself disproves your central tenet that lower corporate taxes equates to value generation. apple is fully taking advantage of lower corporate taxes, yet it's unable to invest its massive hoard of cash fast enough to generate any additional value. that money is literally wasted by sitting in apple's bank account.
if more of that cash had been distributed to employees, some of it would have gone to buying more consumer products, like iphones (economic velocity), and some of the more enterprising employees would have decided to start a new venture (value creation).
Shareholders own the company, all its assets and all its profits. Without their willingness to allow their investment, assets and profits to be kept in the company, it doesn't exist. Suppliers and employees are only part of the equation because they are paid to be, and if they don't like their pay will walk at the drop of a hat.
If your business becomes unprofitable your shares can be rendered worthless, and you can't "quit" and exchange worthless shares for ownership in a better company.
I know you didn't say this exactly, but it is not true that a company exists solely for looking after shareholder's income. They also have other things to look after, such as social obligations.
Here is an article with some more detail about it (PDF): https://centres.insead.edu/social-innovation/who-we-are/docu...
Tim Cook is worth around a billion dollars, he has massive personal resources to pursue charitable activities on his own. Should he reduce the dividend an aging widow depends on to use corporate resources instead?
My own take is that paying staff more than necessary can be counterproductive because it can lead them to retire early or feel wealthy enough to leave for less stressful or more enjoyable jobs, thus disadvantaging the company.
You mean "shareholders's income". It's not Apples income to run social programs with.
Lowering (or preferably eliminating) corporate income taxes benefits investment at every level, from Apple all the way down to startups. If your business plan shows that if you hit plan you will generate $1M in profit your first year, and will reinvest $600k in the business, the rest going to CA and US taxes. Now contrast that to the reinvesting the full $1M in the business. In the second case the business will be able to grow faster and increase company asset/equity value faster, of course it will be more valuable. And this means it's more likely to get funded.