MSRP did not exist back then, you know that.
I know that, but it's completely besides the point here. If regular gamers had any common sense and waited out a little bit for prices to stabilise before committing to a purchase, then scalping would have never been a thing. If you desperately needed a new GPU for work, that's a different story.
All I did during that awful time is sell my 5700 XT for £600 (that I previously bought for £450) and buy a 2070 for £500 instead. Buying anything else would have been stupid.
My point is that Nvidia released the 3070 Ti for $599 and the 4070 Ti for $799, which is a 33% increase by default, before any scalping could happen. They are not GPUs of the same category, so it's only natural that one is faster than the other. How much you bought it for is irrelevant, and so is any similarity in their model names. Smoke and mirrors. What matters is their release price and performance class.
Similarly on AMD's side, the 7800 XT is the successor of the 6700 XT, not the 6800 XT. It's an MSRP of $499 vs $479.
Edit: If you're looking for an Ampere card with the same release price as the 4070 Ti, it's the 3080 12 GB which is only 14% slower. Just a note, the performance difference between the 6700 XT and 7800 XT is 33%.