It would be a sweeping accusation to call all altcoins scams in disguise, since among them there are many legit ones which have been there for years (lites, doges, you name it), but the total majority of "brand" new coins popping out here and there, now and then, are just that...
I guess the entire world hasn't seen as many scams throughout its history as there have recently been in the crypto part of it
litecoin and dogecoin wont ever replace bitcoin or even compete with bitcoin, they don't offer anything new.
there are some altcoins with potential but none of them seems to be replacing bitcoin anytime soon.
that being said if bitcoin keeps being this averse to change, an altcoin might eventually come to replace it, because it just fails to adapt or fails to scale quick enough.
Bitcoin is not without drawbacks. They are well known, and it's a pity that contradicting petty interests of powerful groups within the Bitcoin community don't further the elimination of these drawbacks and shortcomings. On the other hand, you obviously underestimate the inertia of people. It is now evident that it would require a lot more than just some fancy feature (or many fancy features) for a new coin to overtake the throne...
In other words, it may well happen that such a coin that could and would dethrone Bitcoin will never be born
