Because it only works like that for the simplest questions.
Ask Google any slightly complicated question through the search interface, where the question domain is complicated and not necessarily even the question itself, and the answer will be shit. The answers will be wrong and the alleged citations will not only not support all of their respective claims, some of them will not even speak to the specific issue they are supposed to be citations for AT ALL. It will also claim crazy shit like that it is giving you information verbatim from its training data, then do the usual obsequious "you are quite right to push back on that" shuffle when you point out that this is impossible.
Maybe paid Gemini is less shit, but I'm that case Google is doing themselves a gross disservice with their Gemini-powered search results, because the only thing they have shown me is that Gemini is shit, and I'd be a total moron to pay for it.
Either Google is going to have to dig into their pockets to pay for real Gemini to produce search results, or it's impossible and Google will NEVER achieve what you say they should achieve, and they should fuck off right away with their AI search fuckery.