Bizarre thread, but interesting.
If the question is saying Liverpool folded into oblivion right now, I'd barely watch the PL let alone choose another club. I certainly wouldn't pick a club because I like the city or political affiliations, because each club in the league has good fans and nobhead fans, and each city in this country has nice people and crap people, it's all the same. Leeds, Forest, Newcastle etc sing horrible stuff about us, but they all have loads of Labour MPs, it makes no difference.
And whilst I like Palace as a club and have mates who follow them from when I lived in South London, I might go and watch the odd game but I wouldn't care. If Liverpool disappeared it would end my passion for top level football completely. I now live in Macclesfield, I go to some of their games when we have a free Saturday and would probably just spend my Saturday's watching them climb up the non-leagues, but I'd do so without that passion and emotion I follow us with.
But, if the question is who I'd follow if Liverpool FC had never existed, well I'd be an Everton fan, 100%. If we'd never existed none of the stuff I dislike about them would exist either so Everton would be Liverpool basically, just the club in my home city me and everyone I know followed. All the culture and Liverpool-specific stuff that made Liverpool FC great would have flowed into Everton over the years instead (some of it already has obviously) and I'd probably follow them with every bit as much passion as I follow Liverpool.