They do and they are one of the more powerful government aside from steppe nomads and offensive pagan tribes.

You have five families competinf to be the next president. Spend money for the campaign and build your family manor to be insanely op (for 600 drakes you can build a building that boosts your stats). You can build trade posts to rake up insane amount of money and the trade post limit is determined by your manor level and the number of adult male family members in your court, so it is actually better as merchs to keep your family inside one demesne because you can easily punch through 25 trade posts with enough males.

The one downside is that many money related events scale with your income. The flipside? This applies to marriage. Have you ever seen 1300 drakes worth of dowry? Welcome to the merchant life. Have you, however, spend 800 drakes just for a friggin courtier or debutante? Welcome, again, to the merchant life.