Neonchameleon
Legend
YMMVThere's been quite the deluge. I'm not happy about the quality level; my son loves dragons but was severely underwhelmed by Fizban's; he thinks the 3PP The Book of Dragons for 5th Edition - Dungeon Masters Guild | DriveThruRPG.com was a lot better, and I'd tend to agree. I recently got Tasha's for £17 on amazon, fine at that price but if I'd paid RRP as I did for Fizban's I'd have been severely underwhelmed. The Essentials Kit was the last WoTC product I bought that seemed worth the money, whereas most of the pre-2018 stuff I have seems decent. By contrast there is a lot of very good 3PP material out there now. WoTC seem to be going from a scarcity model to almost a 2e-style shovelware model; I preferred the former.
I find Tasha's a much better and more interesting book than the much more trite and pedestrian Xanathar's - and when it comes to player facing content those are basically the only two books in town. Whatever you think of the Wyld Beyond the Wychlight it's certainly not shovelware. And certainly not one of the bad pre-2018 adventures.
And far from being on a 2e-style shovelware model (let alone a 3.X one) we're still on a 1e pace. By Wikipedia we had a core or supplemental rulebook in 2018 (Mordaniken's Tome of Foes), 2020 (Tasha's), and 2021 (Fizban's). By comparison 1e had Deities & Demigods in 1980, the Fiend Folio in 1981, and the MM2 in 1983. And that's before the floodgates opened in 1985 with a whole three (!) core or supplemental books and 2 each in 1986 and 1987.
We've had as near as I can tell 11 published adventures in the same four years; you might even argue 15 if you count the Strahd reprint, and the starter box advbentures. Looking at the list of TSR adventures in the five years before the floodgates opened in 1985 (i.e. 1980-1984) I'm only going to name the famous ones because there were so many. Listing them there was A1-4 (Slave Lords), AC 1-3, B3-8, C1-3, CB (Conan the Barbarian) 1-2, CM 1-3, D1-2 as a compilation, Dragonlance 1-5, EX 1-2, the G1-3 Against the Giants compilation, I1-5, L1 & 2 (The Secret of Bone Hill and The Assassin's Knot), the solo adventures MSol 1-2 and MV1, N1-2 (Against The Cult of the Reptile God and the notorious The Forest Oracle), O1-2 (one on one modules), Q1 Queen of the Demonweb Pits, R1-4 + 6. S3 (Barrier Peaks), S4 (Tsojcanth), U1-3 (the Saltmarsh trilogy), WG4 (Tharizdun), WG5. X1 (Isle of Dread), X2 (Castle Amber), X3-8. So 1e, even before 1985, was on a significantly faster pace than 5e for publishing official adventures.
There is however one difference where 5e is faster. It's produced seven different setting books in those four years of which I think three (Ravnica, Theros, Strixhaven) are M:tG tie-ins and two are streamer tie-ins (Acquisitions Inc and Wildemount). Leaving just Eberron and Ravenloft.
In other words, other than in numbers of settings published 5e's acceleration means that it's catching up with the slow half of the AD&D 1e era. This is an acceleration, but there are reasons that, before the rise of Critical Role, I was joking that 5e was D&D: the mothballs edition.