To call the tall grass at a place like Erin Hills fescue is an oversimplification. I have been in that stuff (and similar tall grass at other courses in the midwest) and there are all sorts of different grass and flower varieties in there.
That is the first problem. As I understand it from my Super buddies, fine fescue (which is what you want to play out of Mark) requires the kind of soil that Adam described - sandy, low nutrient - to remain in that playable state, and to not have to compete with all those other thicker grasses. That is not what we have in this area, for the most part. So, even if fine fescue is planted, it has a tendency to get out-competed by other grass types that thrive in a less sandy soil. Designing a course as a links (or simply calling it a links) does not necessarily mean that it is built on the right kind of soil for playable fescue grass.
The second problem is along the lines of what Adam described. To keep it thin and whispy, it has to be cut with special machinery, and for some sites, those areas need to be regularly top-dressed with sand. Especially given the size of those tall grass areas on some courses, that is cost prohibitive to do.
Curtis at Old Elm has done a really nice job of creating playable fescue areas, as has Eric at Essex County. They are beautiful and fun. However, to hear them describe what they have to go through to maintain those areas, it is not a surprise that most courses just decide to go with the look (which is also nice) and not worry about the playability.
That is what I have been able to pick up on the subject. t. Adam, any Supers on here, or GCAs, please correct any of the above that isn't quite right.