There are HGVC "deals" I would not take for free, and others I would pay for.
If you are given a unit with yearly fees of 21¢ per point and your AVERAGE points cost per night of lodging is 1000 pts/night, (not going to get you into newer HGVC properties) you are paying $210 per night plus booking fee and local taxes. Many of the lower point packages are at the 21¢ per point number.
Some of the higher point resales are at 14¢ to 15¢ yearly fee per point level and as such you could pay as much as $1 per point and be better off over 10-15 years of use.
Or, you could rent from VRBO etc for about the same nightly cost with no long term commitment.
Timeshares are really about intangibles, not $ value, even on the resale market.
Your math makes no sense to me.
Lets work some examples:
HGVC miami - 2BR 7k points for a week.
Hotel rooms in the area (1 BR) are renting for $400/night+Tax (7 * 400 = $2800, this equals a savings of over $1k/week and better accomodation) There are no local taxes on that reservation.
Eagles nest - 2BR 7k points per week (again no local taxes)
Hotel room nearby = $300/night + tax. again, you are saving money (~$630 + taxes) plus are in better accommodation.
The locations where that redemption sux (probably break even or slight loss depending on your preference) are Vegas and Orlando.... almost all the other HGVC locations have savings on this type of deal.
I think of the "buy in" as a sunk cost to get into the rental discount club. If you pay more, you can get a better discount, if you pay less, you get a lower discount.
I paid nothing, and as a result, my discount is less than years, but my cash outflow was also significantly less, and I get the exact same experience on property as you and my commitment to the product is also very flexible (unlike you who would need 10-15 years to break even on the deal).
The reality is that for the most part, people do not know what their lives will be like in 10-15 years. Many people don't even keep their homes for that long, medical things happen, Divorces happen, Wars happen, accidents happen, job cuts and recessions happen.....
Buying something with an expectation of breaking even in 10-15 years is not a good business decision. For example, Walmart expects to break even on the construction of a new store within 2 years (many businesses usually also expect that 2-4 year range on capital investment).