Earlier quoted context omitted.
> They are not keeping up with the state of the art. Does that mean that the performance is middling (making them -IME- equal to UBNT's APs), that they never have APs that use the very latest and greatest WiFi version, or both?
Both. They don't have access points supporting 6 GHz wireless or 2.5G Ethernet. I think they've just given up on that sector, and they're focusing on more specialized outdoors/long-distance wireless. I don't want to get into the Ubiquity ecosystem because it's typically all-or-nothing plunge. And I distrust complicated managed systems out of general principles.
They have several APs that have 2.5Gbit ethernet (one with a 2.5Gbit SFP+ cage), and one AP with a 10Gbit SFP+ cage. Additionally, all their APs run RouterOS, which means that you can bond links together to fairly-reliably get additional throughput. [0]
In regards to Wifi 6e and Wifi 7, it looks like Mikrotik takes quite a long while after a new Wifi version to release hardware that runs it. I expect your assertion that they've given up on 6GHz for home/small-office APs is incorrect.
[0] Yes, I've personal experience with using link bonding on Mikrotik hardware. As a knowledgeable someone would expect, it usually provides you with additional throughput proportional to the number of bonded links.