Are there still people holding worthless altcoins?
Of course. Some people are just holding them for too long, and then they become not worth even selling, if there is no exchange, no buyers, and just a chain, which is slowly collapsing, when it is hard to find even non-pruned peers, willing to serve you next blocks.
Do you still have any altcoins in your holdings like this that currently have no value at all?
Yes, I have some CPU coins, where it is more difficult to sync the chain, than to mine next blocks.
There was a time for altcoins when it was possible to make a lot of profit but that time is not there anymore.
Well, there are still many altcoins, where mining them, and selling on the spot is still profitable (or just more profitable, than mining BTCs directly with the same hardware). Many altcoins are not designed for traders to profit, but for miners. They exist only to be mined and sold to someone, who wish the coin will be worth more over time.