Yes. Main. fees will keep going up. Over the last 10 years they appear to go up at about the rate of inflation. So in 2002 you might pay around $550 in such fees. Maybe increases $15 or so a year. That means in 10 years you'll be paying $700-$800 to get your 150 points. A STUDIO might average 15 points per night....so in 10 years your cost would be about $75/night for a "Deluxe" quality room. These go for $200-$300 today.
Assuming you pay upfront (and don't take out a loan), you would pay $11,250 in year one (actually, $10,500 with the incentive currently in effect). Then just the maintenance fees. $550 this year...$650 in say 5 years....etc. Over say 20 years that is similar to paying say $1,500/year every year (rounding just for a clear example). In other words, $11,050 in year one ($10,500 one-time purchase and main. fees), $565 in year 2, $580 in year 3, etc. is similar to $1,500 in year 1, $1,500 in year 2, $1,500 in year 3, etc. when you compare it over a long period of time.
You mention "190 points for a week at BC". I assume you are talking about a 1 Bedroom. This is a 700+ square foot 1 bedroom suite with a full kitchen, washer & dryer, living room. Not even comparable to a regular hotel room. It's cost is like $500+/night if you're paying cash.
So maybe your 150 points gets you 5 nights in such a room for your $1,500 per year. Averages out to about $300/night for this room. That's like paying $270 + 11% tax on a "regular" hotel room at the Beach Club. Which is 300-something square feet. 15 years from now, $300 for a 700 square foot suite steps from Epcot will be an even better deal.
One more way to look at it....
Purchase price of 150 points: $10,500
20 years of main. fees: $15,200 (assumes 3% inflation in dues per year...$565 in year 1, $992 in year 20)
Total cost over 20 years: $10,500 + $15,200 = $25,700.
$25,700 / 20 years = $1,285/year.
For an average cost of $1,285 (ignoring the "cost of money"), you could get 10 nights in a room about the size of a regular hotel room or 5 nights in a 1 bedroom suite. An average cost per night of $128.50 for the "studio" and $257 per night for the one bedroom. Less than half of what you would average paying "cash". Much less than half would be my guess.
And in 2022 you would still own DVC, with the right to get your 150 points per year for just the maintenance fee. It's resale value would no doubt still be several thousand dollars. Maybe even over $10,000.
For all of this to "make sense" for you, you'd have to be willing to spend $250-$300/night for a 1 bedroom suite on Disney property (or $125-$150 for a studio), and you'd have to travel to Disney fairly frequently or go through the hassle of "renting" your points to others.
It's not for everyone, but for those who plan on going to Disney fairly regularly and are willing to pay the rates I mention, it is a good value.