What if the Republic of China (= Taiwan) was not forced out of the UN and retains its seat in the UN security Council? Will Macao and Hong Kong become part of the Republic of China? And how will the People's Republic of China react? And what else will be different?
Not going to happen.
Eventually, the US is going to have to recognize that 1/4 of the world's population exists.
The Security Council seat was for the colossus that China (could be). Taiwan is not that China.
The longer the transition waits, the worse the final result likely is for Taiwan, IMO.
Could 'KMT as the legitimate government of all China' have lasted long enough that Hong Kong is transferred to it? Maybe. Could the Brits have 'renewed the lease' with the KMT early (like in the '60s). Probably. But that would require action in the '60s, probably, or maybe early '70s, and I can't see that as likely.
Would Portugal have dared p.o. the mainlanders that way and done the same with Macao? I really doubt it.
Ummm... The only possibility I see for actually keeping Taiwan in the SC seat until today would be if Communist China imploded into a state even worse than OTL's North Korea, possibly splintering into multiple warlord regions. But that's very unlikely. IMO.
Not ASB. but I'd call it close to that unless someone can come up with a reasonable scenario.