It's getting there, slowly, because a lot of the initial bootstrapping problems have been worked through.
Lets say there are 1,000 decent engineers in a country and they get hired by various western companies and it's all a great success. They're very happy, obviously offshoring there works well, other companies pile in and hire 10,000 engineers. Ok, are there another 10,000 decent engineers in the country? Probably not, but maybe you can poach some of the 1,000 and use them to train up the other 10,000. But soon there are openings for 100,000 offshored jobs, then 500,000. How many well trained engineers are there again?
That ramp up takes time, and it's not just a matter of smart people, it's relevant experience. If you have two countries with the same number of competent trained people, but in one of them 5% have directly relevant experience, and in the other 50% of them do, that's a massive advantage that cannot even be solved with money.
Then there's the fact the the most talented and experienced people move out of the country. So for every 10 engineers that get to top tier, 3-4 of them move to Europe or the US. So, not only are these countries losing those people, but also they're losing out on all the juniors they could lead and train up. Hiring there is like trying to fill a leaky bucket.
None of which is to say this is impossible, or that it isn't worth doing, or that it won't work. I've seen it work, and the company I'm at now has reaped huge benefits from offshoring. You just need to go into it clear eyed and with the understanding that it has to work for the people you're offshoring to, and that country as well, and you need to be adaptable as the situation changes.