DVDs rot after a while. Can’t be sure you’ll be able to watch them indefinitely. Def recommend ripping it and backing up the copy periodically for archival purposes.
While this is undoubtedly true, the lifetime is almost certainly a multiple of whatever it is on a streaming service. I have working DVDs older than Netflix's streaming service.
Oh I agree streaming is not an alternative if you want to stay in control of your library. Just DVD are probably not great for foolproof long-term archival.
Burned DVDs rot after a while (and quite inconsistently between brands), but pressed CDs and DVDs – such as retail movie DVDs – barely rot at all.
There have been manufacturing 'incidents' in the past, also with audio CD's. Some of my old Aphex Twin CDs rot because one big UK manufacturer screwed up production in the early 90s.