alt Hacker NewsAn important point is that "capital" is essentially just another way of saying "investment". Investment is what creates opportunities and demand for labor. Strong demand for labor increases wages e.g. construction wages going through the roof because of data center investment.
If you disincentivize investment, economic surplus tends to shift toward rent-seeking behavior which creates relatively little labor demand. Many economies in Europe are poster children for this phenomenon. Ideally you want an economy that strongly incentives investment over rent-seeking.
Absolutely not! The word "investment" according to most definitions in most economics classes would encompass the activity of merging together all of the companies in a sector for mega rent extraction. They would even call that a successful investment! If you want investment to create jobs, you must ensure it is going somewhere with a track record for job creation. Historically, the export sector did a good job of employing people per unit investment while the asset sector did not. In general the point is that you have to check.
There are circumstances in which tilting tax, labor, trade etc policy towards capital is actually good for everyone, in which trickle-down economics actually does work, but they are rare and specific, typically apply to developing economies, and are not nearly as universal as they are portrayed in the typical American econ class. Here's how you judge: look at interest rates. Real rates, not nominal rates. The price to rent money. Is it high? Then the economy knows how to productively deploy a marginal dollar of capital, as evidenced by people willing to pay to do it. Is it low? Then the economy has no idea how to deploy the marginal dollar of capital, as evidenced by its willingness to let you try for dirt cheap. In the latter case, proposals to shift tax, labor, and trade policy towards capital are simply propaganda put forward by the wealthy for purely self-serving reasons.