Statistics said:
In 1952, Taiwan's GDP Per Capita was 3.99 times that of the mainland, in the next 7 years, China managed to close the gap to 1.72 times .
From then onwards, Taiwan's GDP Per Capita started to boom, until it reached 25.54 times that of the Mainland in 1994, and since, the ratio started to fall as China's economy took off. ( 3.71 times in 2011). (Exchange rate factors ignored)
The data showed us 2 basic facts:
1) Taiwan, developing peacefully under the Japanese, was far more advanced than a Mainland plagued by wars and insurgency.
2) Arms races always slow the economy. Taiwan was not doing well in the 1950s because of the high military pressures from the Mainland. And the Mainland did terribly in the 1960-70s partly because the pressure to keep up militarily with the Two Superpowers ( Of course, ignore Great Leap Forward and Cultural Revolution was devastating)
Solution:
a) From (1), the simplest way for a Taiwan-wank was to avoid Sino-Japanese war and Pacific War. Give Japanese Taiwan more time of peaceful development (and trade with RoC), it's easy to wank Taiwan.
b) Between the Sino-Japanese War and China's open up, Taiwan's OTL history was already extremely lucky considering the great turbulence going on in the region. Sure, 228 should be avoided, but Taiwan
could have been easily crushed in the clash of Titans (Sino-Jap War, Pacific War, China Civil War, Cold War) if things turned out a bit different (e.g. Nimitz won the debate and launched the invasion of Taiwan).
c) If Taiwan invested heavily (US$ 5-10Billion as Chen Lifu proposed) into the Mainland economy at its lowest point when it's just opening up, Taiwan today pretty much owns the Mainland economy, sadly they didn't.