It is a crime. Ask how many scalpers pay taxes on their resold items. The answer is always $0.
This is incorrect on several different levels. Ebay would be the one to collect sales tax on an item sold on their platform. Ebay would also be the one to send the seller a 1099K. Should the sum total of sales net a profit that year you will be taxed on your profits by your calculated income level the year the sale was made.
If NVIDIA would not remove NVlink few years ago you'd completely skip all this buzz and buy another 3090Ti from eBay for $800-1000 and get the same performance with even larger VRAM 48 GB vs 32 Gb in 5090
SLI/NVlink does not work in the ways you implicitly and explicitly say. Two 3090 Ti's do not mean you get double performance. Best case scenario you would get 35% more performance. The amount of added stutter also makes games nearly unplayable even if they are supported. Also, each graphics card only has access to its own memory, not both. If both cards have 24gb of memory they that is all they can use, you don't magically get more vRAM usable in the manner you suggest.
EVGA did that for the 30-series, and their cards still got scalped anyways as people with low order numbers flipped them and people who’s estimated ship date was months and months out paid to scalper prices rather than wait.
The only solution is to flood the market with such a volume of MSRP priced options very soon within release, so as to give scalpers very little appeal and very little time to work.
I was one of the lucky few that got an EVGA 3080 10gb 2 weeks after release because I clicked notify me early after the release. I did this to every listed card they had on their site at the same time so I got notified when my time in the queue was up for all of them. Of course I only bought the FTW3 Ultra I wanted and passed on all the others so the next people got notified for their turn. The vast majority of people who got an allocation like this through EVGA did the same as I did.
There are actually more solutions to this economically, but no consumer likes to hear the answer. If demand outstrips supply, the item should have been priced higher to begin with. If the 5090 was 5,000 or even 10,000 dollars MSRP the scalpers would be unable to do what they do because this is towards the top limit of price anyone in the market is willing to pay for the cards. Once demand decreases at those prices the cards would go on sale at a price that matches demand until everyone that can afford one gets one. Then the price would lower again, rinse and repeat. People unwilling to pay for it at 5k will wait until everyone that is willing to purchase it at 5k has one and then the price has to lower to make further sales. If you are forever unwilling to purchase the card when the price settles at whatever demand allows it to, that means that you could never have afforded the card in the first place.
The reason these cards have historically never had enough supply at launch is because of how the silicon for these cards is divvied out to begin with. A 5090 requires a chip to be too poor for their GB100 GPUs and Nvidia are not going to be using their chips that are good enough for a GB100 for a GB202 because they make wayyyy more money on their H200 systems which utilize them.