Created Wednesday 11 March 2020
Broadly, they have a habit of breaking badly precisely when you need them the most. There are reasons for this beyond your usual "IT stuff breaks a lot," mostly owing to their existence as aggressively marketed packages of sellable products, and not well thought out academically or community tested systems. One major reason for this is that they exist at the wrong level of abstraction, by tying too many things together under one walled garden, you are forced to use the variety of tool that they allow you, which frequently isn't the best one possible. Consider, e.g. back when you could buy an all in one printer/phone/fax machine/copy machine: They did lots of things, none particularly well, and when one part broke you couldn't use the rest of it.
Moreover, I have strong, mostly unheeded, concerns about what these might do for academic freedom — if we were all forced to use the same textbook publishing house or similar, there would correctly be hell to pay. LMS are a similar situation.