For all those going on about the bookies over/underrating certain players. Let's just say the bookies very rarely get it wrong
Most books aren't that accurate, which is why almost all of them ban professional gamblers. It's simply cheaper for them to produce odds of mediocre accuracy and boot those who are capable of exploiting them. In tennis, the only ones that don't do this are Pinnacle, Greek, IBC and SBO (and the latter three not being really relevant because of poor prices and low limits).
At a guess, I'd say tournament winner odds would very likely be a market with a higher % of recreational gamblers, for practical reasons as well as mathematical ones (longer odds produce considerably worse bankroll growth at the same edge, because of the drastically increased variance). Can't prove it though, my database only covers odds related to individual matches.