Earlier quoted context omitted.
Most people in Europe don't need Lawyers to submit their taxes. In fact, until I started my own company (UK) - I didn't 'submit' taxes. It was calculated (and taken) automatically based on my salary and otherwise declared income.
This depends a lot on the country. For example: I'd say most self employed people in Belgium use an accountant to file their taxes. Some (a subset) of those also have a tax lawyer who helps them optimise certain things. Self employed people (i.e. entrepreneurs) who make decent money will have a tax lawyer, because inevitably, you'll bump into an unfriendly tax collector somewhere down the road.
For self-employed people there are many more rules and regulations: How to write off which kind of cost and purchase, filing VAT if required, etc. so that's already cost efficient if you hire someone qualified.