It still remains, even a good gemologist usually can't tell the difference. And that's why it isn't really pushed. That's the biggest reason most high value gems are laser etched. You got to have paperwork.
There is a process, you need a hard vacuum, a source of power, and minimum or zero G. And you can grow huge diamonds, are those synthetic? Then what about pearls? All too many natural gems have flaws, and more and more the customers don't want those flaws. But who determines the pricing? It's too much opinion based.
Right now, the gems that have skyrocketed in value are some from Madagascar, and those have quadrupled in the last two years, but only because of the difficulty in synthesizing them, and most of the collectors are going to extremes, to get paperwork on them, just to ensure their value.
The Diamond Cartels are doing cartwheels to artificially keep prices high, vs letting the market determine the value.
So how do you determine what's natural or synthetic? Paperwork, and we all know how reliable paperwork can be. So how are most people even going to start to find out which gems are natural or not? Knowing some of the big players in the gem market, I'd be willing to bet that there are substantial synthetics that have the right paperwork behind them, and that's why you haven't heard about the strides made in material science, since the 70's.
Let's just put it this way.....somebody is paying lots of money to keep those gem production facilities in business, and where are the output of said factories going?