While I do recognize those concerns I'll note that it is still a viable model and not just for indie devs. Look to the DAW world (Ableton, FL Studio, Bitwig, Logic, etc.) if you're ever curious about building a sustainable business model around a flat pricing structure.
You listed software that range between $500-$15k. Last time a “I want the option to pay for my software” posts here I replied to was about Infuse. And people complained that “$80 is an absurd amount for a software” and “Why isn’t there a free version?”
A software that costs $500-15k is only feasible for a B2B type business.
> Photoshop All Creative Cloud £59.99 pcm (£720 pa)
> this last one ^ bundles all the proprietary adobe “rented” software they mentioned into one package.
And the worst thing about that 'package' is that if you need (say) just Photoshop + Illustrator - well suddenly the 'cheapest' way to do that is paying for the entire package of garbage that you don't want and will never need.