I suspect that there is still a base level of support for vinyl (among the 'audiophiles'), and these people will be the ones trawling the second hand record shops, charity shops, Discogs, etc. The re-introduction of new vinyl, as a fashion thing, allowed these people to buy new vinyl again. Not from a huge catalogue, since record company policies on what they actually pressed and released seems to me to be bizarre (although only really judging by the small selection in places like HMV). However, this reintroduction of production has been supported by sales, and a slow growth, probably as more titles (including new titles) have been added to the new vinyl catalogue.
I think it might be interesting if the sales of second hand media were available. I'm pretty sure there's still a healthy trade in physical media, just that it doesn't register with the like of the RIAA, because it's effectively a grey market.
The great advantage of digital media is that, once sampled and stored, the duplication cost is zero, and production capacity is infinite (server bandwidth aside). The catalogue of available 'new media' is everything ever sampled and stored, not just what we have managed to shove through a small capacity vinyl or CD pressing plant, and stored in a stockroom. There is never a "I'm sorry, sir, we don't have that in stock, and it's out of print" problem.