I think the real problem with altcoins or majority of them is their short term goal view, not only that, even investors of alts also have this view which automatically either put pressure on some of the genuine alts devs or motivate some of them to want to take the easy route.
Decentralized network, anonymous (but not scam and genius) founder are one of strongest support for Bitcoin growth after many years. Altcoins can not have that especially decentralized network.
I see Ethereum has very long term vision and it has built up a very big ecosystem that is biggest amongst altcoins. Very little altcoin projects can have something similar to Ethereum about vision and success.
Btc has passes through stages of development and improvement in years but alts wants to achieve this within a short period.
Bitcoin is not the first cryptocurrency but it is the first one that makes lot of noise and achieves great success. After more than 13 years, Bitcoin now is a biggest pillar of cryptocurrency market and blockchain industry. It plays a role like a gold standard, I suggest to call it as Bitcoin standard for other cryptocurrencies (alternate altcoins) to rely on.
Even altcoins tend to rely on or don't tend to rely on Bitcoin, they are still affected a lot by Bitcoin.