Bitcoin is not the first at all. It's just the first that worked. The myth of "better designs" has been around for years - despite that Bitcoin's network effect and overall strength has not decreased, quite contrary.
Nothing new is coming. ETH isn't bettert. BTC is #1 and will remain so.
Perhaps in the past that was a possibility, but that ship has sailed. Too late now, genie is out of the bottle. There is no scenario where BTC fails and other coins succeed. It's like expecting some websites to succeed in 1990, while still thinking TCP/IP might not.