While OP is correct in many ways i do have to say BTC could go wrong in a lot of ways (centralisation or bloat as big threats longterm for example). When BTC goes horribly wrong you're happy to hold vertcoin or such.
And then there are black swan events that can hardly be foretold so this is all idle talk in the end as nobody here has a reliable crystal ball to see the future.
Alts always were and always will be where the innovation happens. Bitcoin can not exist without altcoins. I personally do look at crypto as a spectrum, a machine with a lot of cogs and wheels. Cryptos support each other in many ways often by accident or without the awareness of the many. It's not "this coin vs that coin"; it's "coins vs fiat"
Altcoins are part of bitcoins' ecosystem until bitcoin becomes part of the ecosystem of something bigger (which will be born among the alts) which hasn't happened yet and probably won't happen this or next year. Anyone who says he knows what the future for bitcoin holds further than 3 or 4 years into the future likely is a scammer and schould be avoided imo. There is no way of telling what might happen down the road.
There is only one thing 100% certain: the coin that could rival bitcoin will NOT be sold in a presale or ico
