Do the current owners of capital principally hold their money in cash? If they're holding their money in ownership of companies and things, then their wealth wouldn't be destroyed as (current) monies became displaced by bitcoin.

No they mostly own assets, but they need control over the money supply to ensure they don't lose control of the assets. How would the GFC gone if they did not have control of the money supply?

I'm not convinced. If I own a row of houses, bitcoin displacing dollars won't change that.

If you just own a row of houses you are not part of the 0.01% who are in control of the money supply.

If I own so many houses (or other such assets that aren't simply a pile of dollar bills) that I'm part of the 0.01% (since you've changed the argument from "owners of capital" to "0.01%"), the dollar being displaced by the bitcoin as currency of choice doesn't change that.

It does when the interest rate you have to pay on the mortgages you have over the properties can no longer be controlled. If you were the owner of many houses in 2007 and we used bitcoin rather than dollars you would have been in for a world of pain.

Nah someone just needs to gift Donald Trump a fat stack of it and it'll be recognized as genuine legal tender in no time.