This is all very experimental and you can see it as bitcoin is still in the test phase, we don't have yet everything developed to the fullest and thus we don't have or know what else can be built with blockchain in general. I don't find anywhere official where it states that eth is 2.0, could you elaborate?
So the cryptocurrency's first generation is BTC (1.0) and second generation is Ethereum (2.0).
Blockchain 1.0 addresses the first generation as Bitcoins and forks. Blockchain 2.0 looks at extended functionalities.
What will Bitcoin do to stay relevant in Blockchain 3.0.. 4.0... 5.0 ?
Bitcoin needs to solve its transaction issues to have any chance at staying relevant in any of the future Blockchain versions. With blockchain projects like NEM doing about 4000 transactions per second, I wonder how bitcoin's 7 transactions per second will compete against that.
NEM is not the only one, you have steem (although you need account to transact there), nano, iota and some other coins that run on "ordinary" blockchain with a tweaks such as eth and ltc with faster block times. At least these are that I am familiar with, but I can't deny the fact that there will be more of them in future or if more exist today.