It depends on how optimistic, I feel:

• Very - Digg died and Reddit rose, MySpace died and Facebook rose. "For everything there is a season, and a time for every matter under heaven: a time to be born, and a time to die." Reddit and Twitter are enshittifying rapidly and we are here for when people wake up.

• Not very - Big Social Media has reached critical mass/achieved escape velocity and they've hoarded all the "fuel" (people) that got them there. Other places aren't going to take off like they did without hitting some unknowable level of active users and so growth is slow (if there is any growth) which creates a Catch 22 situation. It is easy to see this as all doom and gloom but the Fediverse is growing and may well wander across the threshold in which a positive feedback loop of growth starts happening at which point it seems like a viable alternative to the masses and they leave in droves putting the old places into a death spiral.

• Not at all - most people just don't give a fuck how the sausage is made as long as they get enough attention and have no incentive to leave. Elon Musk good live stream himself barbecuing puppies and enough people would be able to shrug it off because they don't want to lose their few thousand followers and all the little dopamine rushes that Big Social has trained us to rely on.