There is the "small business plan" which reduces it down to $500/year, which isn't outrageous, but it's still $500 for something I probably won't get that value out of because of the likelihood of the project ever finishing.
Instead, I'll find other ways to do it. If Qt was free under $X, $500 under $Y, and $$$ over $Y it's a much more persuasive argument. Unreal manage it :)
I'm not sure how they can prevent you from transitioning from an open source license to a commercial license? You can develop your app for a year either as open source or privately without releasing anything, and then decide to purchase a license? Not sure if I'm missing something, but how does could they prevent this (legally or practically)?
I don't think I've ever seen a Mac app which consisted of only one file. The whole idea behind .app apps is that they consist of several files.
I don't know of any applications whose scope would require to use Qt to come as a single file.
The installer (be it dmg, exe, pkg, whatever) will, but then it's not a problem with the LGPL.
I've spent some time working on a desktop application I hope to sell, but I wont consider Qt, because I'm not even sure I will follow through and finish the product. When it's just a hobby class side-hustle, my first step isn't giving Qt $200 this month, and $200 next month, while I work on my side project for 2 hours a week after the kids go to sleep.