That seems like a function of how much the owners of the new company value their integrity and how much of a price they extract from Zuck if they do sell. At some point, not selling to FB could be a currency (the new upstart could pull talent which would otherwise not want to work at FB).
> FB is not going to fall like MySpace did
"History doesn't repeat itself, but it rhymes."
I suspect we will have to check back in on the health of Facebook after another 6 months of the COVID-economy ravages the advertising market. I think FB will be able to see the need to pivot; whether they are able to is not yet known.
> I find it unlikely that FB will be dethroned unless government steps in.
I think more likely users will just leave/atrophy on it like Gen Z largely did or possibly just suffer a slow death if global advertising doesn't recover to previous levels.