Chances of maxing out potential have decreased as a whole in SO7, whether intended by design or not I think everyone is agreed on this. Though it is still possible to max out a horse bred from on older dam, though harder than from a younger dam and sire, still it seams easier than in previous versions where I too wouldn't really attempt it. This is one of the 50+ horses in my current crop of 2yo from a 14yo dam (so 12yo when in foal). By no means one of my best 2yo, buy still ok on potential and proves it is possible to max out potential from an older dam if you want to attempt it.
This is the sire:
This is the dam:
And finally, the latest 1yo from the same dam & sire (so in foal as a 13yo):
Most of my Dams are 5-12yo. So long as they produce horses I can keep that are maxing out potential, running fast and winning Group races I keep them. Few last past 10-12 though.
And yes, they are photos and not screenshots. Taking a screenshot of SO7 on my laptop in windowed mode is like looking at an ant on google earth!