Completely agree with no ranking points for The Olympics.
Athletes etc. don't get ranking points for playing: it's the medals for you, and your country. If that's not enough, don't go.
As to the Davis Cup, it's a bit strange but they've tried it without points and then with points. And obviously decided that without points was better. Don't know why .... would be curious to know the reasoning.... anyone know ?
There's been a fair bit of comment in the press in recent years, mainly about the points system being unfair in that it only applied to the World Group. Also players from countries with a number of closely ranked players could lose out if they weren't in the team, and possibly therefore affecting their rankings and seedings. The timing of the various rounds isn't good from the point of view of the top players, so it isn't surprising that they choose to miss DC in some years.
Can see the point about only the World Group and imbalance/unfairness.
My own view is that until they make the Davis Cup every two years (with the Fed Cup the same, in the in-between years of the Davis Cup), they saturate the product, both for the players and the public, making the players less keen to participate (because, who cares, there's always next year) and the public a bit blasé.
I think that there should be points on offer for both, and for lower DC groups albeit less points commensurate with average rankings of divisions ie however many points they would be likely to get on the regular tour at that level.
They already lose out on the lack of prize money. We want to see the best playing, but why should they lose out on money and points.
My personal feeling is that DC for the World group at least should be every four years (two after Olympic year), with adequate points and calendar changes so that the top players would want to play it.