For the record and from the GP's context, I'm going to assume by 'harder' you mean 'difficult to use UI'.
I'd assert 'difficult to use UI' is the incorrect type of 'hardness' or 'difficulty' that should be present in an enterprise piece of software. Mainly because fighting a UI is non-value add to the goal of the user. The user's goal, in this case is to manage their books.
Because of this tension of QB _purposefully_ being at odds with the user goal, I'd expect start-ups and new software products to gobble up QB market share over time. If this is the case, all QB can do is make it more difficult for current users to switch off them (.QBW file extension?) as their market share slowly dwindles and their channel sellers slowly disappear.
Good 'difficulty' should come from the learning curve it takes to master (i.e. accurately, quickly, and reliably) the task at hand.
FWIW I'd expect purposefully building difficult-to-use products has many negative externalities for the company culture and this would be a big red flag for any future Intuiters.