Per day spending? No.
Aggregate spending? Not even close.
The problem is the Early DVC "deal" was advantageous to the customer...it evened out...and now is trending toward "advantage

isney"
The membership would be wise to start swapping out or do things OTHER than wdw. sure that's a "part of the program"...but they want no part of you going anywhere but a Disney park. They want want you haven't already give...the discretionary cash. That was the point.
Now if you say "most products get worse over time...what's the problem?"
None...that's a consumer market.
But most products fail or can't hold their price longterm either.