How would Bezos continue to have power if people stopped using Amazon? Most of his wealth is in Amazon stock. Sure, he'd have a few billion left over, but his real political power comes from his companies, not his money.
"A few billion" places his wealth in the top .0001%. It's telling that even in this far-fetched scenario where Amazon and Bezos' "real political power" are destroyed, he's still much more powerful than the vast majority of US citizens.
You seem to be equating wealth and power. Wealth and power are certainly related, but probably on a logarithmic scale. Someone worth $20,000 isn't twice as powerful as someone worth $10,000.
The primary source of political power Jeff Bezos has is his control of a very large employer. Employing lots of people gives you some power over local politics in the areas where you employ those people, and it gives you some level of influence with politicians who might be interested in ensuring you continue to employ lots of people, because it's good for the economy.
Your run of the mill billionaire heir/heiress that doesn't really do any useful economic activity doesn't have a huge amount of political power, in general. They probably have more than you or I do, but not a ton more. Certainly not more in (linear* proportion to the wealth difference.
Once you realize that the relationship between wealth and power is logarithmic, it's not really a super concerning relationship. There are other sources of power that are much more important, and much less transparent.
