The hobby will "always" be there for "old" coins !
There may, at some very distant future point, be little to no "new/modern" cash/coins minted, but that will just bring "more" interest to have that "old" 2009 coinage...

.....and even likely, the early 20th Century...let alone
ANY coin in the Nineteenth Century or before.
I think there will be up and down "rollercoaster rides" of interest
A.L.W.A.Y.S. in coin collecting....but that it will never disappear.
But mainly I believe that it's "the past" that will always be a collectible thing.....no matter what they implement with ideas of a "cashless system" and/or any future "new" coinage.
There will always be people who like to collect "old stuff" that most other people don't have.......so NO MATTER WHAT THEY DO....WE'LL ALWAYS HAVE THAT ! ....

And maybe future "Proof and Mint Sets" might
only contain NIFC coinage !....