The vast majority look like they've been licensed and relicensed numerous times for Poundland style retailers or the 4 films on 2 disc compilations so there's not a great deal of monetary value. The odd one turns up here and there but even then it's a gamble on what condition it's gonna be in coming from the shelf of a charity shop which has a big say on resale value. One day I'll drop on that trove of Roger Corman era Filipino exploitation movies!good call...and cult rare finds like that sometimes fetch a bit online. The used-market for media like DVD's, Blurays and also music CD's/Vinyl is really active. And the less mainstream, the more demand.
not sure if you could call it a counter-movement to streaming, but there does seem to be a lot of people still preferring to own their own films & music via physical media.
Definitely like to keep a physical collection though to complement the streaming services which as good as they are are still always subject to the whims of licensing, remasters, cuts and changing values. Plus there's the nerdy appeal of a collection.
Either way the ease of access and variety offered with streaming, the steep drop in value of physical media outside of 4k discs and the fact that even pretty ordinary home TV's are light years ahead of what was available 20 years ago is a bit of a golden age for film fans.