[Wowfunhappy]

> That sounds to me like an app built for 10.7 Lion would not run at all on 10.14 Mojave... something that is probably true for real Macs as well.

In practice, on real Macs, most apps built targeting 10.7 Lion will work on 10.14 Mojave. Some apps will be a bit buggy but still basically work.

If you asked about 10.7 and Ventura, then I'd give it more like a 50/50 chance the app would work (possibly via Rosetta 2 depending on your hardware).

Backwards compatibility on macOS is quite bad, and it has gotten much worse in the last few years in particular, but it's not quite as bad as some seem to imagine.