I do not follow the coin market per se, as my collecting is a hobby and focused on my own interests which are narrow.

However, the speculator mindset is very strong these days across many domains and speculators create bubbles all the time in any market. If people are collecting for numismatic reasons, the hobby is pretty longstanding and stable, but if people are "collecting" with expectation of future profit, this will burst once they sell, and it tends to accelerate as more sell and prices drop.

So some coins will maintain value, some will rise, and some will drop. The coin market is full of many markets which I do not think are strongly related (the fact people are paying for W quarters doesn't change Morgan dollar, silver, or Lincoln cent costs, etc).

Overall, I think speculative bubbles will pop: either when the speculators give up, panic, or demographic realities set in.