Goalposts are firmly planted, we've always been discussing wizards, not ditch-diggers etc.
But what "being a wizard" means, in training requirements and social role, is *not* firmly planted.

I note that a first level spell cast by an 11 Int wizard is *just as good* as one cast by a 20 Int wizard, unless you need high DC, which for civilian purposes you don't. Depending on edition Int can matter for speed of advancement, or how many spells you get per day, or how easily you can learn a spell, or the highest level spell you can learn and cast, but in D&D it has never mattered for the actual spell cast.

Also edition details can matter a lot. In 3.5 a 1st level bard gets a handful of cantrips; in Pathfinder she gets infinite cantrip slots *and* potential access to Cure Light Wounds. In the latter game it would make more sense for your entire 11+ Cha nobility to have dipped into a level of Bard just for easy access to curative magic. In the former game it's less appealing, in AD&D the question doesn't even make sense.