"Why is this man so dense? He never responds to the subtle clues I carefully place behind a veil of plausible deniability."
If you're trying to make a move without making a move, that might be the reason he's not responding. You're asking him to take on all the risk of misinterpretation. At some point somebody has to be overt. If you're presuming it should be him, you should ask yourself why you think that.
You're spot on, I no longer deal with said "veil of plausible deniability"
This is 100% how I approach all sorts of relationships in my life, not just romantic. That's called direct and open communication.
I will straight up ask (politely) that someone clarify what their explicit stance is, if they refuse or try to play coy about it I simply let them know I don't know where they stand and I don't know what they want.
I've done this with bosses, siblings, my son, and my partner. I have grown to respect people much more because I understand them better and have also cut out some toxicity from my life that I didn't know was eating away at my happiness.