I don't know about "most", but I know friends that, collectively, own Wyndham, Hilton, and Blugreen & they are all LifeTime commitments.
We debate the pros and cons of lifetime vs
<50 years all the time.
A few things I've observed since owning DVC, and comparing notes with these friends:
Resale values for DVC are much higher.
Their Maintenance Fees are higher.
One of them still has a fixed week, and its in Williamsburg VA in January (She can't even give that away)
I get a real chuckle when we talk about planning to vacation together in Orlando.
They all boast about how "close" they can get to Disney (the irony is priceless)
ET