Hmm that’s not exactly that. The courting MAY be one part of the issue.
But really, it’s mostly about what we did for the character. I’ll say it again, but very often in a story that would be romance driven, the MC would literally save the RO by romancing them. It is that romance, that love, that saved them - for many reasons.
And then another character can hook up with them. And they don’t go through all of that, but the RO is seemingly fine. So what was the point? In the end, they weren’t truly in danger, or they didn’t really need that love that was deemed so special when romancing them.
I like the trope about love saving someone - in one way or another - and visual novels / text based games do offer romances like that on a regular basis. But then if a random character can get to the results of making the RO happy and safe without any effort and without going through the whole character developement arc of the RO, and without all the happy and sad moments etc, then what was the point in doing so for the player / MC?
So yeah, I don’t need a perfect courting simulator, but if there was complicated courting on the MC’s side when romancing the RO, then it should be just as complicated or more for another character to do (as in, high chances of failure etc). And mostly, they should go through the same hurdles, with the same chances of death and so on.
In case of a romance that truly saved the RO, like getting him out of depression or saving his life in a literal way, I wouldn’t mind if they hooked up with someone else if not romancing them, but then the game showed clearly that they are not as happy as in the good endings if romanced by the player, or maybe even they’d die, because that other character wasn’t the one who could save them…
I have a hard time explaining it better than that, but I hope I did convey the things I feel for that in clear enough way!
Edit: maybe imagine you’re weaving a beautiful tapestry, and the result is gorgeous. This is the romance/route of that RO.
And then someone next to you purchases a machine-made tapestry with the exact same design, and it looks just as pretty, without all the effort and pain and stuff… You sure can think yours is better because it’s legitimate, but you’d still feel frustrated and may think “what was the point of all that if it could be achieved so easily?” - that’s how it makes me feel