Will altcoins ever return.
In short
Some will, yes.
Others will not. For example, Bitconnect will never return. The last exchange delisted it a few weeks ago. In theory, people could send it to each other and trade it personally for illegal purposes but that would require two rich guys with endless money never willing to give it up. Thus BCC is effectively 99.9% dead.
On the other hand, there are absolute steals out there right now. E.g. Disney backed DRGN, BLK (Presently just under 8 cents a piece, previously about $1.08) and various other altcoins most certainly WILL make a comeback. So long as the community still supports them. And Disney is not a quitter. Blk was supposedly having a token burn and there was massive confusion about that but it does not appear to be very widely supported. (I did not burn any of my nearly 5,000 blk. (Every penny is a $50 movement).
It could just be that the guy behind the burn wants all of your blk and to give you something I have never heard of (and thus am 100% avoiding) in exchange.
I am buying now for cheap and holding until the inevitable then cashing out and laughing at everyone that did not believe me.
(Be smart, stay safe, sell when you make a large profit, don't hold too long due to greed or you may lose it all).