It happens to almost everybody. Since I'm referencing Langley and thus Washington, they've lost McGuff to Ohio St. and Neighbors to Arkansas. Just lost their football coach to Alabama after leading them to the Championship game. Have lost their last 2 volleyball coaches, one to Notre Dame which was a definite step down in that sport. The other to Minnesota which is a bit better gig, but not by much if you look at UW historically. But better money in the Big 10...which of course UW will now be a part of.
Very few schools are immune to getting their coaches picked off. Money is almost everything.
Agree with virtually everything you're saying.
Jim McLaughin, the volleyball coach you mention, is an interesting guy. He's coached a Men's (USC) and Women's (Washington) team to the NCAA Championship and he, without question, did his most-known work at these Left Coast schools.
Before taking those schools to the heights, he spent one year as an assistant. While there, he met his future wife, an assistant coach in another sport (I think soccer?), who was from the northern Indiana area. They got married and she followed his travels. When the ND position came up, he cited that "it was his turn" to make a move on behalf of his wife, whose family was still in the ND area. While I'm sure Jack Swarbrick, the then-AD, offered a boatload of cash, the family reason was also crucial.
p.s. He did a great job for the three years but had to resign because of a back condition that caused so much pain he couldn't fulfill day-to-day activities in the gym.