That's a really good way of putting it - the Knight is in love with the idea of love.
I remember I guy I knew years ago who was very eager to get married. Period... who he married was totally secondary to the notion of being married at all. (I see that more often with some young women, but in this case, this guy was total romantic, at least in theory).
At one point, he was burning through women at a very fast pace because he'd leap straight from hello to proposal and the more thoughtful ones quite sensibly backed off. In the mean time, a few of them were predatory enough to really take advantaged of his singleminded willingness to commit to anyone who'd stand still long enough to let him. After witnessing this, a group of us actually did a sort of compassionate confrontation and sat him down with some 'rules' to follow - like before he proposed he had to go out so many times, introduce prospective women to us (his group of friends), find out a scavenger hunt assortment of information about them (favorite pet as a kid, etc... all the stuff you'd find out over time actually getting to know someone), etc.
Kudos to him, he actually changed his approach until it felt more natural and when he did marry it was after a year long courtship and they've been together for about 17 years now.
But when he was doing his Knight of Cups thing? Proposals were easy. Having the necessary thoughtfulness to actual make them a good proposition was another thing entirely. It took taking the focus off of the concept of love and onto the person as an individual.