Sure, create the technology, some will use it. Some will even abuse it. But there are some six billions of people in the world right now. Just because a technology exists, or is cheap, doesn't mean everyone's going to run out and use it.

You haven't shown that cloning technology has the utility of, say, electricity or the car - items that have become part of the fabric of society. Will parents want a smarter kid, or a stronger kid? Sure. Will they want one that's so improved that he's not really theirs anymore? Will they want a kid who's so smart he scares them? Will they want one who's so graceful he makes them feel downright inferior? Most won't - most people are still pretty hung up on seeing their own gene line move forward, they want their kids to have a large part of themselves in them - but most are also quite keenly aware of their own imperfections, so direct duplicates are likely to be pretty uncommon. Consider: with adoption an available alternative, with the option to buy eggs or sperm from exceptional donors, a lot of people will still spend a fortune at fertility clinics to have their own children.

So you get a set who might be willing to let a doctor pick through their own eggs and sperm to find the best of those, maybe even mix-and-match their own genes directly. But the results of such an effort are not going to be earth-shaking. Maybe avoid the unwanted recessives, spare the kid the risk of a family history of breast cancer or heart disease. Maybe have a kid who's a good bit brighter or more athletic than his folks - but not quite an Isaac Newton. Not the kind of thing that's going to send all of us out hunting down a doctor, least of all if the "nurture" end of things doesn't improve - an athlete born to a pair of couch-potatoes isn't likely to learn the attitudes that will lead to stellar status, and as a result his life story's not likely to motivate other couch potatoes to follow his parents' example.

So, the procedure becomes the exception rather than the rule - something for people whose grandfather died of cancer, or who are strongly motivated for other reasons. Perhaps a very few opt for wunderkind. However, the majority of genetic transactions continue in the time-honored manner, because the majority aren't willing to sacrifice their own genetic future and don't see enough benefit in the most acceptable alternative. And as a result, the overall impact on the gene pool is minimal. Psychology plays a role that may, that will likely, falsify your "truism".