The big question is what is fescue? The next is what do you want it to look and play like.
All the solutions above help but ultimately it comes down to the grass seeded. The biggest issue with fescue "native" areas is that they are seeded to be a sod ie have structure and therefore creeping fescues (chewings and creeping red) are used. The issue is with these, is once they establish they get dense and since they are not regularly mown (or maintained) they grow thatchy and lay over and are generally thick to the point where they swallow balls and if you are fortunate enough to find your ball, they'll snag your club.
As mentioned above, rich soils, fertilizer and water all compound this by feeding the plants and making them healthier so they grow better. So in most cases where the fescues become unplayable or don't look whispy, it's due to the areas being seeded with these species. Creeping red and chewings make sense on fine turf where the ultimate goal is a dense surface (although maintaining them is a whole other discussion).
The best way to have successful fescue "native" areas is to seed them with the true bunch type (whispy) fescues - Sheeps, HArd and Blue fescues. These do not creep and each one is an individual plant. The issue here is they do not create a sod or a dense turf so there is possibility that a ball may land on soil. Over time (many years) they will fill in but they still will not create a sod. The easiest way to describe the difference would be using a sod cutter - with the creeping varities you can cut the sod and lift it, whereas as soon as a bunch type is cut it will just fall apart as you try to roll it up. For soil stability reasons and to create a sod all the seed mixtures have a creeping variety in them (even if it's at a low percentage) but in time the creeping variety takes over an ultimately dominates. The creeping varities also grow in quicker which is why they are specced. Some architects like seeding the roughs with fine fescues so they can adjust the rough/native lines as needed and this necesitates a sod, so it is difficult to avoid the issues later.
When we built LedgeRock that was the number one request and 14 years later overall the fescues are playing as they should although there are still some problem areas where there is no way to avoid them getting hit with water (and sometimes fertilizer). I also added little bluestem and annual rye to the mix at LedgeRock. The rye was to provide quick establishment to get the areas stabilised but after the first year it died off. The bluestem was to make it look a little more native and add variety. It is an extremely slow growing turf but the results are great. The fescues grow in the spring and we mow them after they drop their seed heads (The point where they lose their whispyness) and then the bluestems take over providing a nice red/brown color for the fall. I know the bluestems are frowned upon for some reason (they can get really long maybe) but used correctly they are a great addition to "native" areas as they are also bunch type.
Lastly these areas are not maintenance free - the only real savings are not mowing them frequently, but in most cases they need to be mowed 2-3 times a year and sprayed for weeds (including other turfgrasses). Depending on the property this is easier said than done, especially if the terrain is hilly. If timed correctly some of the other grass eliminating herbicides can thin the fescues a little if the timing is done right and one of the plant growth regulators can thin them a little also (although I haven't had a lot of success with that method). Flail mowing and burning in the late fall can also help with getting rid of weeds and helping keeping them thin for the following season. Lastly I have heard that spreading rock salt can help thin the fescues out also - which makes sense as turf plants do not like sodium.
Shelling them out and adding sand will help in the short to mid term but eventually they will still get thick. Meaning the best method is is to seed them only with bunch type fescues (and live with soil voids that may result from that), and then keep up with the ongoing maintenance to keep them as they are intended.