Why?
Obviously you've had bad experiences with your past dealerships but not every dealer is as poor as the ones you've experienced and you should perhaps re-consider that notion.
One thing that I see on this BB often which always amazes me is the opinion that "techs" working at independants should somehow have more knowledge and/or real experience than an experienced, educated dealer tech who's been through Volvos factory training and repairs Volvos everyday for living compared to a guy who only occasionally does some minor, easy maintenance on a few Volvos that come through the door. Do all dealer techs everywhere have experience and education? NO. All dealers have new guys (as found in every business everywhere) BUT most dealers should have at least one guy who's a master tech or close. Believe it or not, sometimes you have to request that a master tech or tech that you know there works on your car or it could be dispatched to the rookie guy (happens unfortunately) but these same type rookies also work at independants so that part's really not exceptional there either. Do indys have Volvo master techs with recent Volvo experience and training? Maybe, some do (those who've left dealerships) but it's not a rule by any means.
In my many years in the auto business, I've worked for a few indepenants and dealers too and I prefer to work for a dealer as they pay for all schooling, buy all the latest tools and equipment and pay better than any local independant. The independant owners do not pay for factory training during the workday so those guys are usually on their own and thus don't bother. I've seen many independant techs apply and come through our doors too but they never last long because they (almost always) tend to be hacks and are then fired for poor workmanship (too many combacks) and in todays Volvo dealership, good CSI is a very BIG deal. Our dealership averages 95% CSI which is better than average so maybe we're not typical?

Most of the cars I see that frequent independants are some of the poorest maintained Volvos we see in our shop (yes, they all end up by us sooner or later) and they're in what I'd consider "marginal condition" when compared to those which are maintained the way that the manufacturer (Volvo here) advises them to be maintained.
Our area also doesn't have what's known as a "good Volvo only" independant as those locally might only have a few guys that have some experience with older Volvos, like 200s/700s, no one locally has any "real" FWD Volvo experience to speak of. I've heard that there are some exceptions to this trend in other major cities but not my area and I've been around more than long enough to know.

Another point, although I'm sure that there are many DIY types like you here, almost ALL of our customers are upper middle income types who really don't ever want to open the hood and look at the engine compartment and they can afford to take it to the dealer. If I wasn't already a tech and had the money, I wouldn't want to work on cars either anymore as it's really not "fun" for most people.