They should. The reason you don't see any videos dated before May 1 is because ALL videos were released then (or at a later date).
Chess.com videos
Yea don't worry about it, chess.com pay those titled players to create those videos so they aren't just going to delete them! 
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Hi all,
I just registered with chess.com and the earliest videos I could find are dated May 1 '09. I like to take a slow pace and I'd much rather watch the videos when I feel like it & have the time to do it!
Seeing no video dated before May this year could suggest that videos get erased, which would be quite sad news if true.
So TLDR: Will the existing videos remain online? can I watch some of them e.g. in Christmas (when I'll have time...)?
Cheers,
Penta