No it doesn't "negate the point" in any way or form. Nobody who is buying a 3060 now is going to upgrade to a 3070 down the line UNLESS they are in a situation where they can only find a 3060 and they have enough cash to spend. Anybody who has the budget to buy two GPU's for a relatively minor upgrade has the budget to just buy the 3070 outright.
I'm going by the actual MSRP of the cards. Prices are currently inflated because of the shortage which is yet another reason why your comparisson isn't a good one.
Comparing it to GPU performance just doesn't work that well. If you buy a 3080 or even a 3090, you're going to be playing all games maxed out for years to come. You're basically buying it for extremely luxurious options such as 120hz/4k or 240hz gameplay. The price difference for those two cards, which is JUST THE GPU, is several hundreds of $
Meanwhile the difference between a Series S and a Series X is losing access to entire features, being forced to play at 30 fps in some cases, no 4k, much smaller SSD and no diskdrive for only 200$. The price/performance ratio between a Series S and a PS5: DE is even worse.
Buying a Series S only to upgrade to a Series X is downright stupid if we're talking about a situation where both consoles are equally available.
Your notion that you read the mind of every potential PC card buyer is massively flawed. First of all, they may have the money, but don't want to spend it on GPU. If they play at 1080P/1440P they may find a 3060 just fine.
Second, you have zero idea how long someone will keep a card. MSRP is also meaningless unless we are actually selling at them, which we are not.
Of course it's the same, 3060 to 3070 or 3080 to 3090, all of them have similar feature sets up as you go up you get faster frame rates and resolution. By your almighty declaration though, you can decide to go from 3060 to 3070, but then 3080 to 3090 is magically maxed out? So better tell nvidia then, no reason to sell a 4080, I mean after what you said, nobody will buy one, they will be playing maxed out for YEARS on their 3080 or 3090. You really have no idea what you are talking about.
There is barely any loss of "features" from X to S. Both play games, both do it pretty well. It depends on what a person values, and I hate to break it to you, not everyone values things the same way you do.
Lastly, I can't even agree with the last point. If someone has just enough money now, and wants to play some xbox games NOW, there is really no issue with buying an S for now with the intention of getting an X later. Yes they will lose a bit when they sell the S, but so what, in the meantime they get to play xbox game and or perhaps access gamepass, something they could not do if they buy nothing.
Ridiculously arrogant post by the way, there are people on this board who have bought an S with the intention of buying an X later, you just called them all stupid.