You mean $1,125 plus tax. Your return was likely $1,000 minus selling and shipping fees (which for eBay average around 18% if you don't have a store). If someone paid $1,000 direct for that card (HWS or Facebook marketplace) they got robbed (although there still is a 3.5 + 50 cent fee). $800 USD is the going price for the 2080 Ti on those kinds of places and they come with their own set of risks. Of course eBay does too but the risk is less.
So really the cost of having that card is: (Sale of prior GPU) - (Initial investment amount + cost of upgrade + transaction, sale, and shipping fees)
Your equation would look like this ($1000) - ($1125 + $1500 (assumed price of new card) + ($1000 * 0.18 + 26)
Your total investment: -$1,831
If you sell your $1,125 card for $1000, that's not you making $1000. That's you recouping a portion of your original investment as shown by the equation above. It does not change the fact that you are still down $1,125 from your initial investment in the card The $1,500 number about is being generous as well, as the article states it could very well be $2,000, which would bring your total investment over -$2,000.
FYI you didn't get the best possible gaming either. That distinction belongs to higher end RTX 2080 Ti models. At $1,125, your card seems to be a bottom of the barrel model. Given that the 2080 Ti released on September 28th, 2018 your two year claim seems to suggest that you bought at launch (technically the 2080 Ti has only been out for 1 year 11 months). Most decent AIB models were $1,300 or up if you wanted something that beat stock performance.