I suppose then that we have a different point of view as to what constitutes a diverse music collection. A few thousand albums is really not that large and it would be obviously full of omissions to me; both albums I'm currently aware of and those that I have not yet discovered.
If one listens to their entire collection, then a few thousand albums IS large. Every collection, every streaming service is "full of omissions" because they do not contain every track of music that has been produced.
How long would it take you to listen to 30,000 tracks? Really listen to, not just as background noise.
I suppose if your entire music budget for the year were $120, then maybe I could see spending it on the physical albums these days, but frankly, even then, I think someone with such a restricted budget would be far better served by the vast catalogue of streaming music available to them for that amount as opposed to the tiny physical collection they could create with that budget.
Again, it is the "car leasing" scenario. If one is on a limited budget, streaming services give one access to more music than they would be able to outright purchase. Streaming is best for those with small budgets.
My budget is perhaps higher than many. Couple that with thrift shopping for tunes, I'm able to purchase quite a bit of music... oftentimes more than I would be able to listen to.
Streaming services, even those with millions of tracks, have significant "omissions" for my tastes in music since much of the music that I seek out wasn't produced on CD, or isn't part of some package licensing deal.
So for me, those claims of "exploring new music" are not really applicable because either the genre of music, or specific artists are poorly represented (if not completely absent) from streaming services.
And for all of the "exploring new music" opportunity that exists, there is a lot of junk out there. That's time I can't get back.