Bitcoin is decentralized and secure. No one owns it and that's its greatest feature. It was not meant to be a store of wealth or just an asset. It was meant to kill Visa and Mastercard, to put power back in the hands of the people. To eliminate the third party trust system.
Segwit does not make Bitcoin able to do what is meant to do. So We can either come up with a plan to make Bitcoin instant and able to handle millions of transactions a minute or find an altcoin that can work alongside Bitcoin to handle payments. The problem is, if say Dash is used to handle payments and Bitcoin is used as an asset and money transfer, Bitcoin becomes obsolete. Dash can do all of that. Unfortunately, Segwit has not made Bitcoin the better of the coins in most cases. It's also still losing decentralization quickly. But then again, all ASIC mined coins are.
One thing I would want to say is that there is no perfect coin. SegWit have helped bitcoin through the tough time that we were having because of the transaction fee and time but it's still not enough for transactionists. Transactionists want something that's an instant, pretty much a lightning network. Apparently, we don't have that in bitcoin. It is said that they are testing LN to some altcoins but it was still not enough reason for people to refrain from using bitcoin and then fully switching to that new coin.
People will always choose the mainstream over something better. There are people, of course, that would like to transact using a coin with a better transaction time and fee but the question rather resides on if the person you're transacting to would want to use that coin too.
