Well, maybe that's a problem on a super-expensive laptop line ostensibly intended for "Pros".
We can argue until the cows come home about where Intel "should" be, but the fact of the matter is—even leaving aside compatibility—x86 is the only game in town at this level of performance. I'm sure employees at Intel wish they were at 10nm right now just as much as anyone else. I'm equally confident they didn't fall short because everyone at Intel was snoozing all day.
Apple is a design-centric company and has always been one, even when Jobs wasn't at the helm. Their company ideology is much more different than other "engineer-centric" computer makers.
Apple makes "utilitarian products" that are user friendly and approachable. This is why they do what they do and have for more than 20 years.
There are plenty of "performance centric" laptops out there, you're welcome to buy it.
I for one will be getting a specced out i9 MBP soon, it's for work and more than enough for me since it reaches ~1070 Cinebench score on a laptop, which is pretty damn good. I don't mind the trade-off for thinness compared to a fat notebook and I want macOS to come preinstalled and I like Apple's warranty.
I do however, will keep my desktop a Hackintosh as a daily driver. It's rock solid and fast and Apple has nothing out right now that I can purchase. The iMac Pro is out of the question for me.
In the end, Apple is more like an "appliance" company that makes computers, smartphones and tablets and other accessories. Think of it that way.
You're free to not buy their products, and on the Windows side you have way more options.
However, we need to hold up Apple to a certain standard and scrutinize them. I really don't think they should have put the i9 in the MBP without redesigning the cooling system. That stuff costs millions of dollars to R&D.
Most likely the i9 sales will be a pretty small number, so it wouldn't make sense for Apple to spend a lot of money on re-designing their cooling.
They have access to Intel's internal roadmap (which we don't have) and most likely they are waiting for Intel to move to 10nm and 7nm and that's when Apple will completely re-design the MacBook Pro (most likely in 2020) and it will probably be thinner and have a better cooling solution.
However, I've never seen a MacBook Pro (any series) that hadn't had some kind of problem. Apple keeps pushing the envelope all the time, so usually I buy their notebooks that are the last in the series which makes it more mature.