I don't see many people with boutique wheels. My son-in-law has boutique wheels on his bicycle, but he has weight issues and more money then sense.
As for the parts you might want. I used to "require" a certain rim and certain spokes, but now I am wiser. Lower end stuff - Shimano 105 hubs (or similar), Mavic OP rims (or similar), and any spokes, are sufficient for the guys who do a lot of hard riding around here..
I seem to be one of the few riders who has a large number of spare wheels in their vehicle (4 on my 2 bicycles and 3 spares). I also seem to be one of the few riders who has a wide assortment of cassettes on hand.
Since I am larger than normal and ride customs, I'm going to take offense. My weight issue is from being 6'7" and I do make good money.
So how are you saving money (or sense) if you have to have to carry a large amount of spare wheels?
Pre-built wheels have gone down the same rabbit hole as so many racing frames: More focus on marketing and profit than on what actually is good for the rider. I didn't always have this attitude--but my latest pair of pre-built Mavics are such crap, that I just can't agree. My Aksiums are only a few months old and are already showing wear, and their performance is incredibly low. They also forced me to pay an extra $60 over last years price by including some useless tires that are simply sitting and rotting in my garage.
I guess I have no sense either. But no one can tell my wheels are custom. They're completely unlabeled. I didn't have them built to show off--I had them built for those so-called 'special situations', like riding long periods of time without having to worry about them.
I did have one wheel built with a dynamo hub. Actually my wheel builder's nickname is "Doctor Dynamo" because of his knowledge of them. I guess thats a 'special situation', but the fact that the average modern cyclist hasn't even heard of a dynamo hub makes me wonder. I write this because I know so many long-distance cyclists who scour the internets looking for solar panels and back-up batteries to power their lights and devices when the dynamo hub has been around for decades. Im not talking racing cyclists--I'm talking AIDS Lifecycle, long-distance charity types. It makes me wonder which direction the industry is going, and if it is a good direction.
It's reasons like the mentioned dynamo hub, or other 'special situations' that people aren't aware of, that make at least speaking to a custom wheelbuilder worth it.
However, I also learned of White Industries hubs threaded to Velocity A23 rims that make for an amazing ride. Nothing out of the ordinary, just perfect. And a wheel that isn't available pre-built, and I'll take them over 105s any day, which I have already ridden. I used to have 105s on Mavic CXPs. The speed increase from the Whites in coasting downhill is ~8mph on the same bike. Sure I spent an extra $400 on the set than my Aksiums. But so what. The hubs are serviceable with replacement parts and will last far longer than 3 or 4 sets of Aksium or 105-based wheels. Cheapness and value are 2 different things. Fact is tho, Mavic has hardened their aluminum to a point that I don't think they make a good rim anymore. No wonder everyone's gone Velocity for aluminum.
For carbon, it's out of my range. But I think one is truly crazy if they don't speak to a custom wheel builder before spending that much money on such a sketchy material with so many different configurations.
Besides, a good wheel builder is also aware of the good pre-built wheels and won't upsell a customer if one exists that works. The majority of those who purchase customs from my wheel builder are experienced riders who have had enough with whatever they have been riding. Or, those special situations, when one requires a wheel that won't break, such as on a commuter, a touring bike, a bike that has to ride on real pavement, etc. These buyers are more concerned with completing their journey on their bicycle than spending time at the shop getting their wheels repaired. They are people who ride a huge amount of miles--enough that they are able to witness their pre-made wheels breaking down in a matter of months than decades. I suppose they could all be considered special situations, but then there are thousands of special situations here in the Bay Area. Not all of them are rich, nor are they fat. They just like good wheels.