What do you call "reliable?". We use 4 studios, 5 days a week, every week of the year, and there are very few problems, certainly fewer than in the previous eras. I don't mean to be argumentative, but what is your benchmark for "reliable"?
My own experience being more anecdotic than yours, I'll accept if I'm wrong. However here's my argument.
I bought a 2015 Macbook Pro, and I've had a lot of problems I never had with my 2005 MBP, like glitches and dropouts, random MIDI latencies (???), and other issues I'm sorry to say I gladly forgot about when moving away from Mac.
Even when booting up, the startup screen effects (like fades etc.) were glitchy from the very first time (and the dual monitor support made them worse), while they were smooth and glitchless in my previous Mac. Not that this matters in itself, but it gave an ominous bad quality feel from the start - which only confirmed itself later on.
Then a friend bought a MBP for movie editing that same year, and had frustrating issues, like: the USB port believes the HD is disconnected (when it is not), then reconnects and disconnects again, many times in a couple of seconds, covering up the entire screen with warning messages that she has to close one by one manually, before she can even see what she was working on again.
So, sure, those are only two experiences, but it was enough to steer me away from Mac for good. Now I get mad at Windows' issues, but at least I don't get mad at how much I paid for that piece of bugware on top of it. To me, today's Apple quality doesn't justify their prices anymore. (And frankly, while still not great for real time, Windows is much better than it used to be.)
I'm wondering, which generation of Macs do you use? Because older ones are still great... And do you have a technician whose main job is to maintain the computers in your studios, so that you don't have to deal with that yourself? I would love that, but can't afford it.