I usually dive solo, and that includes what I would define as "tech" dives (no direct ascent, whether due to deco or overhead). The more "techy" the dive (i.e., deeper dive, longer bottom/deco time, and/or further/messier wreck penetration), the more likely I am to opt for solo.
Less important reason: if I am spending a lot of money to enjoy diving onto and into a hazardous wreck for a handful of minutes, and then spending the next hour plus hanging on a deco line (if everything goes right and I don't wind up doing drifting deco), the last thing I want to spend any part of that precious time doing is worrying about/keeping track of about a buddy.
More important reason: that person is more of a liability than they are an asset. I don't need them to get down, in, out, back up, and manage anything that goes wrong along the way, but they complicate the already complicated task at hand simply by virtue of their doubling the number of independent actors in a confined, silty, entangly, jagged space pressurized to such a degree that even minor problems tick away gas/time very quickly.