Metabolically speaking, the ale yeasts typically do not ferment maltotriose, so lagers tend to get more crisp from that further fermentation of the sugar.
Partially true. Generally speaking, pastorianus yeasts are better equipped to ferment maltotriose than cerevisiae. However, again, there are plenty of exceptions.
On the pastorianus end, take a look at WLP810 and WLP820, which in my experience have fairly low attenuations averaging about 70% -- not great. Several others only do kind of okay, mid 70s percentagewise but not in the 80s unless a complex or very long mash schedule is used.
Many or most commercially available ale strains actually DO ferment much or most of the maltotriose. Very few struggle to ferment it in a major way -- these exceptions include but are not limited to, in no particular order:
Lallemand Windsor
Lallemand London
Fermentis S-33
Mangrove Jack M10 Workhorse
Mangrove Jack M15 Empire
Wyeast 1099 Whitbread
Edme Ale
Munton's Ale
White Labs WLP002 English
I would also expect many wild yeasts, wine yeasts, cider yeasts, mead yeasts, etc. to fall closer to the latter end of the scale.... but not necessarily.
And then on the other end, many commonly used yeasts such as US-05 and BRY-97 will attenuate into the 80+ percent range every time with ease, regardless of mash time or temperature.
So........ I still find it difficult to generalize such things. I mean, you're kind of right..... but then there are just so very many exceptions.