Is that really still true? I know most apps I use have either required purchasing an update or have simply been replaced by OS functionality.
And there's something about committing to a Mac app when you're not sure if, in a week, one you like more will be available as opposed to iOS apps, which are basically disposable.
Of course all of this is tempered by my desire to support the products I use and the people who develop them.
Same can't be said for iOS apps. It's just a much better investment.