To be fair, it does say DLSS. I'm not saying I agree with the tactic of coming up with a graph that makes the increase look more favourable than it is, but it's technically true and it's how they get away with it. It's not the first time Nvidia have done this silliness, it won't be the last either. It's not exclusive to Nvidia either, Intel, AMD etc they all do the bs graphs and tech youtubers constantly call them all out for it. Consequently I'm not massively convinced the in the know people are still falling for it, only the mass market who probably aren't the ones expressing disappointment over the 5080 either because they don't actually care enough.
I don't think it's any more deeper than it was just a disappointing improvement. It's hard for anyone with a 40 series card to be that excited by it. The price gouging going on because of lack of stock is just icing on the cake to cause people to have especially strong opinions. The 30 series came after the disappointing 20 series which also suffered from a small improvement and reliance on DLSS to sell when very few games actually had it. So when the ridiculous stock issues/price gouging hit the 30 series, it just didn't hit as hard. Not to mention everyone being stuck in doors makes for good reasoning of buying a GPU...