They will produce what they want to produce and what they think will make the most money.
What would make the most money (from TTRPG book sales) is a flood of product aimed at their core fanbase. If they were limited to making money off books...
There's so much more potential to make so much more money from even, say one unsuccessful movie, though, that, instead, keeping the brand stable and it's image solid may be the better bet. A brand your few, devoted fans keep dropping money on even as they rip eachother (and the brand) to pieces in public, may not be the best foundation for striking out into more profitable markets.
I guess I'm not really disagreeing with you, there. The bottom line is that WotC isn't making it's TTRPG products for the people who may actually play them, yes?
Yeah, but did we really need the SCAG Swashbuckler?
Not any more than we needed a 5th edition in the first place, no. Not particularly more or less than a bladesinger or battlerager. But, whoever felt they needed it has it, now, and whoever doesn't care can quite safely ignore it.
One book a year like SCAG probably wouldn't do in D&D from bloat in less than 30 years. Making it to the 50th anniversary would probably be fine, though. 10 years of stability as a foundation to whatever big launch they might want to do (movie, VR game, body sculpting, nation-building, cell phone app - who knows how effed up the world will be in 2024) at that point to finally break through into /something/ remotely mainstream.
From a conceptual standpoint, can't a character that evokes the archetype be created with the PHB?
From a conceptual standpoint the Ranger, Paladin, Barbarian, Sorcerer, Druid, Bard and Warlock could all be created from just the core 4 classes with sufficient application of re-skinning, MCing, feats & backgrounds (and another generous portion of re-skinning). Your GOO 'warlock' is just a wizard with the hermit background RPing all that lovecraftian stuff while casting the same old wizard spells on the same neo-vancian schedule as every other wizard, because mechanics don't matter. Etc.
It is entirely possible to create a system that lets you build to any concept, without needing new 'classes' or other material. It's been done. It's just not D&D. Soooo not D&D.
As for the timespan, I don't think he was saying over 2 years...
Yeah, he was pretty clear abou that, and I think it's a terribly unfair bar to expect 5e to clear. 5e is PH + 1 'splat' (barely) into it's run. That it's two years notwithstanding, that's comparable to 4e PH1 + Manual of the Planes, not the whole run of 4e, which was also little more than 2 years!
Sometimes, I don't know if a given mechanical trick justifies the creation of a class, or even a subclass.
It sure seems like 5e classes are designed with the need for such mechanical distinctiveness in mind.