I got curious, so let's look it up.
Googling, it looks like maybe Netflix has 17,000 titles total in in it's collection internationally in april 2022, but only a portion of those are available in a given market. One page from 2021 said the US catalog was ~5K titles, but I bet it's bigger in 2022 as the overall catalog has grown as much as 30% maybe. So I dunno, let's say somewhere between 5K and 8K titles available in USA market netflix?
How many titles did a typical Blockbuster carry? From 1988: "Blockbuster, for instance, operates superstores that stock roughly 10,000 tapes (about 6,500 different titles), compared to the 1,500 to 2,500 a typical independent offers." —https://www.nytimes.com/1988/05/01/business/a-tight-squeeze-...
(Blockbuster didn't have much/any TV, while that's potentially a big part of Netflix though?)
So it's the same ballpark anyway. Netflix doesn't actually have a whole lot more titles than a Blockbuster did.