It’s really simple, the timely repair of your instrument is more important to you than your luthier. Nobody wants to hear that they are low on the priority list, but that is obviously the case. Why don’t they do the work for you faster? Simple; they don’t have to. Maybe it was fee based, they only charged you what they thought they could get vs the amount of money that would motivate them to finish the job quickly. Maybe they had projects for repeat clients or maybe they wanted to watch their kids soccer game. One of the benefits of working for yourself is deciding your quality of life. So yea, your luthier doesn’t care about your pickup swap.