It is unlikely that such boycotts will bring down Amazon, but the company is share price driven and declines in sales do have an impact on stock prices. In addition, boycotting can make the boycotter feel better. Eating at Wendy's rather than McDs is not a boycott, but deciding to not eat a McDs and then eating at Wendy's would be. Bezos will remain rich, but we can only do what we can do.
Sears used to be the a huge national retailer and mail order company. It started in 1889 selling watches by mail. It reached it's peak in the 1970s and built the Sears Tower in Chicago (tallest in the city at the time) and had customers throughout the Americas. It's catalog had hundreds of pages and sold just about anything one could want. By 2021 after ~130 years it was gone. In our faster paced world now, Amazon could fade (be broken up?) at a much faster pace. All that would take is for some big investment company to buy a controlling share and dictate significant changes. That is what is happening right to Southwest Airlines. I expect them to fade or be gone within a few years.
Fond memories of the Sears Christmas catalog... I'd be handed one and told I could circle half a dozen things I wanted. I might get one or two of the things on the list plus something else they thought I might like (my dad would usually go to my grandmother for ideas on that, which is why I have some of the vintage '70s Barbies that were out then).
Years later I had a paper route, which included delivering the Sears catalogs. Those things were damn heavy, when you had a dozen or so to deliver around a 3-storey apartment building with no elevator.
More to the point, the sort of anger Trump and Musk inspire people can do significant damage if channeled into economic action. It's only a question of getting the millions of non-terminally online people who are angry about the administration to connect the dots to Amazon.
Canadians have boycotted Amazon for a variety of reasons. There's a serial rapist/murderer named Paul Bernardo, who raped and killed some teenage girls in the 1990s. He's been in prison for many years now and will never be released (we don't have the death penalty in Canada, but I'd make an exception for him since he's unquestionably guilty).
Anyway, some years ago he decided to write a book and it was being sold on Amazon. Canadians were livid that this waste of oxygen was attempting to profit from his crimes, so a 'boycott Amazon' movement started. Amazon was clueless about why there were suddenly thousands of 1-star reviews and that we wanted the book removed or we'd boycott, and shrugged - until the Christmas orders started getting canceled and they realized that they really shouldn't piss off Canadians during the Christmas shopping season.
The book was pulled. Yes, it was probably available from other sources, but some were responsible and removed it when they found out just how heinous his crimes were.