here's a Question is there any way that Communist China not get China's Seat into the UN and not recognized by most countries, and if the RoC was legally China up till today what would the world look like?
No Sino-Soviet split might be necessary to prevent restoration of relations with the West.
Taiwan and South Korea would be America's go-to place for cheap manufactured exports up until the late '90s. Not sure if those countries would be so eager to snap up US treasury bonds, but the fact that no single country could account for such a large share of US imports (they'd have to be split up between at least a few) would definitely alter US diplomatic policy in the Pacific Rim.
I'd guess Mexico, Nam and Pakistan would take up China's role in "cheep crap imported to the US" in the 2000s
Nope, not enough infrastructure, education, access to the seas, and most importantly a culturally linked country near-by (Taiwan+Millions of Chinese Ex-pats) willing to jump start investments. There simply isn't another place with all the right ingredients on the same scale as China.