If SSR wasn't build, DVC would have certainly have built as many points somewhere else. Had they completely built VB as per the original project and added a couple of off-site resorts, impact on all WDW resorts would have been much worst. So on average, SSR it's not too bad.That’s a different counterfactual than the one you pose in the last paragraph. If DVC was the same just without SSR all of the resorts would most certainly have more availability all the time, but especially OKW, AKV, and, once it’s sold out, Riviera, because they’re the next largest resorts (besides Aulani, but Aulani will have more declared rooms than owners for the rest of its existence, making booking patterns there advantageous overall).
But if they built 3 more smaller resorts, it’s impossible to predict what would have happened without knowing more about what those resorts would be like.
But it matters only relatively. Because what remains at 7 months is limited by owners booking their resort, not which other resorts exist. The only way to make more availability is to make the resort more expensive
If they publish a different point chart for exchanges and make, let's say BCV cost 2x or 3x to exchange in, then the few rooms that arrive at 7 months would stay available for longer. But I don't think the non-BCV owners would like that.
And in 2024 if, like everyone say, they resell the resort greatly increasing the point charts, demand will decrease. Some owners will still always book there, others might be tempted by cheaper exchanges.
The real problem with 7 months availability is that with the point charts as they are, staying at BCV and BWV is an incredible deal. So people can pay higher resale per point because they have to pay fewer points to stay there. But in turn, this means that if you have paid $200+ for the contract, you're doing so only to stay there. You're not tempted to try another resort that might be had paying half resale and costs more points per night. Hence, reducing availability at 7 months. Which causes resale prices to increase because to stay there becomes more difficult and so on. SSR, VB, HHI or AUL have nothing to do with what's left at 7 months.