Better conditions: it currently seems that these folks are working a very busy location that appears to be severely understaffed if folks are waiting hours. This is a brutal work environment. If you have the appropriate number of techs scheduled at the right times, this would probably take care of a majority of this category.

Better pay: you said it yourself, they jump to the highest bidder and good for them. Be at or near the top of the pay grade and this issue is also fixed.