https://www.reddit.com/r/btc/comments/61sim7/i_am_stepping_down_as_a_moderator_of_rbtc_and/This is actually a very good read so I encourage bitcoin users on both sides of the Core/BU divide to digest it. I've leaned Core myself, but have exactly the same thoughts on his scenarios 1 and 2. Not surprisingly given his R/BTC affiliation he's more pessimistic than I about scenario 3 (Segwit wins), but that matters little as long as its hard to imagine Segwit seeing the light of day.
I'd point out, though, that Segwit does alleviate the immediate TX pressure, and even if TX pressure continued at current levels that would not kill bitcoin - only throttle it. But I'm inclined to agree with singularity87 (the author/mod at the link) that even such throttling may be enough to "kill" bitcoin in the sense that Ethereum will surpass Bitcoin in network effect, leading to the "Flippening." (A period of rapid change as people realize bitcoin supremacy is a lost cause and flee to Ethereum in droves.) So the challenge for diehard bitcoin supporters is how to avoid this outcome.
If you are going to read this article there is a way to overcome bitcoin deadlock and settle all problems coming from miners disagreement and conflict. This time a proposal was made and it plans to create a user-activated softwork or UASF. The goal of this system is to give power to the bitcoin holders, exchanges, wallets and payment processors to dictate and give directions on the changes and the code to be used to improve bitcoin. This way we are not going to have more problems coming from the miners.