I very much agree with the spirit of your post. Sensei isn't the best guy in the world or anything, but he's not as bad as a lot of the posts have painted him. However, I think he understands women well enough to know that sex isn't going to happen with most of them just by being in their proximity. You have to spend time with them, and get to know them, be there for them, for it to become a possibility. So, it is possible that even when sex isn't likely to happen, it's still part of the reason he's doing it - playing the long game.For example: I'm just now playing the event where he visits Yuki, where she distributes flyers ("We have drinks and shit"). Why did he go there? The prospect of having sex is minimal.
"I just need myself to be occupied. Nothing good ever comes from wandering around aimlessly."
Edit: There are a lot of other posts in a similar vein to my call out, and people on both sides of whether he does or doesn't plan that far ahead. I'm not sure it's a specific plan per se, as much as it is a general understanding of how people work, and that it's needed to get to his eventual goal.