I would say its the precise inverse: very few people can do it well by ear, and it takes a lot of practise and experimentation. At the most basic, try matching the volume level of a subwoofer to the main speakers - even this is already very hard to do by ear, for reasons of human auditory perception and psychoacoustics.

You don't even need a lot of "lab equipment dollars", measuring the basics can be done with ~100€ calibrated USB mic. As a rule of thumb, you cannot develop a good speaker without measuring, unless you have advanced modelling tools and experience to use them correctly, in which case the measurements will mostly match the simulations.