You are confusing a whole lot of concepts here, and at times it seems you are arguing against yourself(?).
First you argue against great concentrations of capital also being great concentrations of power, in this "yes, but no" sentence:
>Money is a form of power, it is not equivalent to power.
This sentence seems to mean absolutely nothing. "not equivalent to power" is some sort of vague semantic argument about what power "is", that is not interesting to the discussion.
Wealth _is_ power in the sense that you can use money to affect change in the world. Wealth is the simplest and most flexible form of power, because it can be directed at anyone or any organization, and transformed into other forms of power. And it even grows by itself!
You then talk about the market cap of Amazon. Why?
The market cap, while also representing a sum of money, is not really relevant to the discussion.
You even seem to realize this yourself, but you do not really explain the reason for bringing it up.
Are you trying to say that competition exists and therefore everything is good?
That would be fine if it weren't for the fact that the companies you mentioned do not compete in the same markets.
They share some markets, e.g. AWS vs GCP, but you offer no evidence that this market is healthy.
Competition is key if you want a healthy market, as is aligning corporate goals with societal ones. You could even argue that competition for customer business is the main mechanism for achieving alignment.
If you allow any one business to get too much power, competition will weaken.
Excessive power can come in the form of excessive capital concentration. It can also come in the form of other bargaining chips that come with excessive capital concentration, such as: control over resources used by direct competitors in a market, e.g. the marketplace itself; the ability to create jobs, politicians love jobs; the ability to invade a new market by subsidizing a new department with capital from elsewhere in the organization; or even an information asymmetry created by a huge data collection operation.
Amazon exhibits all these forms of power and more.
Some of the other companies you mentioned exhibit these as well.
It would be in the interest of society to break up monopolies and other concentrations of power that are actively impeding competition in the way that Amazon is.
These ideas aren't new, developed nations typically create institutions to maintain healthy competition.
In the US, the federal trade comission and the DOJ are tasked with keeping competition healthy by enforcing antitrust law.
They used to be a lot more active than they are now, e.g. when they broke up Bell. I wonder what has made them slip...