I'm not the president of the Hans Summers fan club, nor his press secretary, nor his counselor, but I've been in technical business for four and a half decades on two continents and know a thing or two about it; so..
I don't think "Overdue" is the right word. It's not that he owes it to anyone, or is under any compelling obligation: it's his company to run as he sees fit - a company that is subject to market forces, resource constraints and technical and logistical challenges, just like every other. Yes, he announced his intention to release the QSX two years ago: I'm sure he is not blind to the fervor and interest it has caused, nor to the frustration at the delays, so I suggest it is reasonable to deduce that there must be some obstacle yet to overcome; he has certainly said as much in news releases. I'm sure the product would be in our hands were it just a simple matter of getting it done.
Business choices are difficult.The QCX classic for example: while popular, has been a challenging build and/or a limited platform for enhancement for a good number of kit-building hams, hence the recently announced QCX+. The time to bring that to market was not trivial, and neither, I'm sure, was the identified opportunity cost. I'm equally sure he calculated that the need for it was compelling enough to put other projects aside. He has, resulting from swift and vociferous feedback from those for whom QCX+ is not a solution, committed to look into some kind of compact solution for SOTA and highly portable applications. That will take time too.
Success is a two-edged sword, and growing pains are called that for a reason. All we can do is to trust that Hans is striving to achieve that impossible balance between doing what he wants (that motivation which drives us all), what he can (he is only slightly more superhuman than any of us), what he needs to do (for the health of his business), and what he well knows we want him to do (ditto).