Echo the above.
A new dealership can sometimes have a hard time drawing good techs. Many of the ones that apply already have one foot out the door at their current employer, or they might have other problems (drugs, police records, or blacklisted by corporate). A new dealership has to often pay big bucks to get in a proper shop crew, especially for techs who are paid straight commission on their labor. You often find signing bonuses and/or guaranteed minimums for a set period of time until the clientele stabilizes.
No decent tech is going to walk away from a 100+ hour a week flag sheet to an unknown quantity where he might make less than half his current paycheck. Toolboxes have wheels, and they roll to the green pastures.
...and everything fdcg27 said.
EDIT: And then you have to throw everybody in school to get their certs/competency so the shop can get paid for warranty work. Often a shop will pay big bucks to lure in a couple of techs with all of their manufacturer specific certs to ease the transition (as long as you have one or two techs employed with the proper certs, that's all the shop needs). They will then throw most of the other techs, the ones who aren't total washouts, in factory schools to get as many certs as quickly as possible.