Back in 1992, Taiwan might--just might--have been able to pull it off, with a lot of luck. China's international diplomacy hadn't fully recovered from the crackdown on student demonstrators in June 1989, and its power projection capability was still underdeveloped. Also, with lingering Cold War-era reflexes still in place, there's little doubt the US and most of the Western world would have backed Taiwan up. China would have been quite mad about it, but may not have actually made good on its threats of war. OTOH, this may have given hard-liners in the Chinese politburo a timely excuse to make a comeback, and then all bets are off.
Another factor was that, at the time, Taiwan didn't have assets tied up on the mainland, which it now does. This gives China sizeable (and growing) leverage in case of renewed tensions.
But one should also have Taiwanese public opinion in mind. The independence issue is quite a volatile one, but back in 1992 there simply wouldn't have been a majority to support it, and with the KMT still in control of much of the state apparatus (democratization was only a couple of years old at the time), a bloodless coup with tacit public approval would have been entirely possible within days of the incoming administration declaring independence.