If bitcoins are to be a store of value, then casinos and merchants need to adjust for the changing times and consider using alternatives instead.
It shouldn't be that difficult to add a couple more coins, but the development costs need to be eaten somewhere. Only when more gaming sites starting using other coins, and they start to lose marketshare will some of these bitcoin-only sites begin to change.
If bitcoin won't be used and accepted by business, services and merchants it will lose its merit and not longer will be treated as good store of value asset.
Using altcoins won't solve bitcoin's problem - it will create even more complicated situaiton with no main coin used by every service.
We have reached Bitcoin Scalability Consensus. More than 80% the miners, have agreed to SegWit + a 2MB maxblocksize hardfork.
So just stick to the bitcoin, buy more coins, it will be upgraded and retain the top position as king of crypto.