What is the human brain then? I'm afraid you are bound to push so far that humans are no longer qualify as intelligent.
We also have extensive studies on all the ways we are actually really bad at processing input (a by-product of our primate ancestral heritage). There are entire textbooks on all of the different biases we have built-in. And there are clear and obvious limits to our perception, as well (I'm thinking of the five senses here).
Imagine you're neither constrained on the input side or the processing side of this equation. It becomes kind of a mathematical inevitability that we will be able to create artificial intelligence. When anything can be tokenized and act as an "input", and we can run that through something that can process it in the same way that our brains can, only scaled up 10-fold (or more)...
If there is one thing we're good at, it is thinking that we are the center of the universe. I think that is blinding people to the possibility of AI. We can't fathom it, for lots of good and bad monkey reasons.
Living in that sort of bubble must be very uncomfortable. Companies from virtually every category are pouring money in OpenAI starting with Microsoft. Just go and take a look at their partners and which field they belong to.
And remarkable that you cite Microsoft's involvement as some sort of standard of significance. A company that has a long history of non-innovation, alongside its disgraceful history of suffocating and extinguishing actual innovation. Founded by one of the most remarkably unimaginative and predatory individuals in the software industry. I'd suggest seeing Microsoft investing in anything is only a good sign of a potential future rort (Gates' whole history of making money).
Finally, maybe rather than just saying that 'all sorts of entities are investing in this hoopla', try to make an actual case yourself as to what the value case in this technology is. We should try to think for ourselves here, not just follow the (investing) herd.
I acknowledge and am mostly fine with the idea that machines can 'learn'. But they learn (the game of Go, navigating a car in the real world, etc) under our direction and training (even if they potentially go on to surpass our abilities in these tasks). They don't have any agency; they don't have any curiosity; they don't have any 'spirit of consciousness'; they are not intelligent. They have simply been trained and learnt to perform a task. It's a great mistake to confuse this with intelligence. And the field itself is acknowledging this mistake as it matures, with the ongoing change of nomenclature from 'Artificial intelligence' to 'machine learning'.
That being said, in the field of machine learning there are significant things being achieved. I was wowed by DeepMind's AlphaZero and its achievements in 'teaching itself' and playing Go, at a level never seen before. I'm impressed by what Tesla is doing with self-driving. I'm less impressed by OpenAI's GPT-x because I don't think it's very useful technology (despite all the, imo, foolish talk of it doing away with all sorts of knowledge jobs and being able to 'tutor' ppl) but I do recognise that it also marks a step up in machine learning in the area of LLMs. None of this is 'Artificial Intelligence' however, and it is both silly and dangerous to conceptualise it as such.