I think it is much less bogus than you think. Yes, price would change if a large number sell or buy, perhaps that would be more of a statement on liquidity than bogusness.
At anytime, all shareholders are able to sell their shares at the market price, therefore anyone still owning believes the price is at or less than it’s true value, likewise anyone has the option to buy at the current price so (barring non-idealities) everyone else thinks the price is potentially higher than its true value, therefore market capitalization is much less bogus as it is the price where there is balance between people’s capital put towards buying and selling bets on the true value (of course lots of assumptions: low transaction costs, ignoring tax treatment, spherical cows, etc, etc).
It isn’t obvious to me that “credit worthiness for sale” is bad on net. There are the high publicity cases of people committing fraud by way of purchasing creditworthiness in some respect, but there are also (and I’d guess more wide-spread less exciting) legitimate purchases of creditworthiness.
For example, it might not optimal for very competent newer investors/inventors/organizations slowly get capital investment or other support. If you think of the marketing campaigns, sponsorships, etc. as a bond to show they believe in their performance, and believe their purchase will pay off from success, then it is somewhat less concerning and also valuable to do some amount of sponsorship/marketing.
Someone very close to me is a very competent real estate investor, who has had exceptional returns (and I believe exceptional risk adjusted returns) much higher than what most other real estate operators are making for their investments. It is not efficient for him to slowly get investors while others who have had longer to collect investors get more capital for lower returning projects, it makes sense for him to “buy creditworthiness” in a sense, selling some of his share of his investments to entice people to refer investors to him.
Buying creditworthiness allows competent new entrants to get investors/support grow quicker than they otherwise would. Scams will exist, but that is honestly part of the creative destruction of the market (not that they shouldn’t be rooted out). Those that don’t do their due diligence will have a smaller say in how capital is allocated.