If someone creates a ALT coin to compete with BTC for first place, I think eventually that ALT coin will get there. Because at the end of the day, if that 'ALT COIN" makes enough money they can continuously push their "ALT COIN to surpass BTC.
making money is the last thing of importance when it comes to creating a currency! and so far only bitcoin has been a currency which is why it has value and it is keeping it and also increasing it every day as its adoption grows.
so if another better currency was created in the future you are correct.
so far what we have in altcoins is shitcoins made for pump and dumps and profit making. so you make more profit from these shitcoins but they won't even come close to bitcoin ever.