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.
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.
(But you shouldn't. There is little need to distribute closed source software anymore. If you are shipping a binary with valuable trade secrets, then it won't be secret for very long. You can do server-side rendering of all the UI like all the large cap tech companies do then it won't matter if the client application at the edge is open source.)
On the contrary, I think companies are more willing than ever to pay for quality 3rd-party tools and software. The reality is that the Qt licensing costs are a bargain relative to time saved for enterprise customers. It's not even a question at this point.
The complaints usually come from people thinking of lean startups or selling hobby projects, where the licensing overhead is another non-trivial number on your cost of goods sold. Many of the complaints here would only realistically be a problem for someone selling a very small number (<100) of their product per year with very low margin, which is far more rare than people think.
Regardless, Qt still has a separate small business license with a different pricing structure: https://www.qt.io/qt-for-small-business