If not for the reputation that Bitcoin has built over the years as a store of value, memecoins scams would have dragged crypto reputation into the mud. Memecoins are no different from Ponzi schemes, left for then alone cryptocurrency would have collapsed. But thanks to Bitcoin reputable, the name cryptocurrency still holds value.
Every thing you have said is absolutely correct, and I completely agree with you, bitcoin is indeed the reason why there is such a thing known as cryptocurrencies today, it's also the reason why we have a thing known as the blockchain today as well, so lets just say that Bitcoin is the bedrock of crypto currencies, its the backbone of the crypto currency market even till now and till God knows how long because if anything happens right now that caused bitcoin to collapse. It will be a catastrophy because the entire crypto market will tumble and burn to ashes.
But then, we still can't really tell what would have happened if bitcoin failed to succeed, maybe another crypto currency would have succeeded and crypto will still exist regardless, but this discussion for another day..
It's not wrong to diversify ones crypto investments to other Altcoins as well, because even though there are alot of scam in the market, there are still alot of legit ones.