Unfortunately only one of the two forks will win in the end, and the rest will have to follow the winning fork.
certainly you can keep both forks going. if people decide to keep the cores fork, even if XT gained the most nodes, they certainly could (although one or both would tank in price, and both would tank in value).
keep the true bitcoin core going, even if XT the alt, gains traction and majority it'll be shortlived like all previous competing alts.
If the fork happens I believe Core is the altcoin because XT is continuing the original vision of Satoshi. I think the Core developers should create an alt coin and that way they do not need to force their vision on everyone else, that way Bitcoin can stay true to the original vision of Satoshi. Furthermore if you believe that we must have the consensus of the core developers even if that consensus becomes impossible to reach, it is tantamount to centralization of power. The ability to hard fork in this way represents the check that we have against such power that a core development team could hold. This is part of what makes Bitcoin truly so decentralized. If you think that we should never hard fork it is the equivalent of saying that the core developers have absolute power over the development of the Bitcoin protocol. Or as Mike Hearn said "they believe that the only mechanism that Bitcoin has to keep them in check should never be used".
If you really want to continuing using Core after the fork you can, that is part of the beauty of volunteerism. I suspect Core would become like an altcoin where people that really want to use third parties instead of transacting on the blockchain directly can do that. I just do not want to be "forced" to use third parties over Bitcoin, I would stop using Bitcoin entirely if that was the case and move to another cryptocurrency.
To put it simply,
if we do not increase the block size it will be more expensive and less people will be able to use it, that is to transact on the main chain directly. Instead we will be "forced" to us 3rd party payment processors. I would like to continue using Bitcoin directly and have the same level of transparency and security as the clearing houses.
However
if we increase the block size then it will be less expensive and more people will be able to use it. I do think that increasing the block size is the most decentralized option. Even if full nodes will only be able to be hosted on powerful computers. I am a miner myself and I do not think that this will effect decentralization of mining because miners do not run the full nodes, the pools do. The pools function in a similar way to a representative democracy, the difference being is that I can switch my miners over to another pool within seconds. It is important to remember that the Pools are most often different entities then the miners themselves. It is the miners that decide, not the pool operators, the pools serve the miners.
I do urge everyone reads Mike Hearn's article on why we should fork. Please be rational and apply reason and decide for your self what kind of a Bitcoin you want.
https://medium.com/@octskyward/why-is-bitcoin-forking-d647312d22c1