You can't complain about this. You want to skip the queue, so you pay for it. Like you said, you'll get money back from health insurance and tax relief.
You might complain to the Govt about public waiting lists, which is where the supply or demand issue comes into it. New entrant consultants have been on lower pay than their colleagues since austerity measures. It is very hard to attract them to fill all the vacant posts as a result. If you don't have a consultant, you don't have extra outpatient clinics.
Like another commenter said, all professionals have a fee and that's life.
The fact that they may dispense their knowledge in 5 mins is irrelevant, as it is expert knowledge, gained by many years of hard graft. I'd feel much more confident if a consultant took a few minutes to diagnose me than an hour hemming and hawing over it.