> They basically just accelerate by full grade or two while raising the expectations for each kid to another level.

That's...not accurate. Gifted programs tend to increase the degree of personalization more than anything. Yes, most people who qualify for gifted programs at probably going to end up targeting at least a full grade up in each core curriculum area, but the programs don't do a straight bump.

> This is unnecessary burden on kids with a high risk that they can lose confidence or even burn out at tender age not willing to learn anything any more.

Gifted programs are actually targeted narrowly at a segment that is more at risk of burning out by being subjected to the unmodified mainstream curriculum.

> I think there are probably 1 in 1000 kids who are going to earn PhD by the age of 18.

There pretty clearly are not.