Forms and patterns are everywhere in fiction, and they might seem limiting. But they're really not. Even the worst show ever made is a lot better than it could have been, because it was able to use narrative techniques from past stories to frame itself into something viewers can try and follow.
Well, this is saying that it's better in uplifting weak shows, and in that I agree, but that doesn't necessarily mean it's a net gain, after all it could still be seen as constricting to stronger shows which can stand on their own merit. Of course, in that case existing patterns can be disregarded, and this does often occur in exceptional shows anyway. I agree with your general point that they're more likely a good thing, when they're used, but there's still a factor of limits to them, and that's a worthwhile trade-off in some cases and not others.
That's the thing: people complain about constraints in how genres are constructed, but if we got rid of those constraints you just know people would complain even more. We could be "more realistic" by showing the full time needed for people to walk to places, show them going to the toilet, and show them sleeping for 8 hours.
I reckon you were going for argumentum ad absurdum, but it seems more like a strawman since going to that level is neither something people really advocate (well, except maybe as an exercise for students of film and drama, not intended for consumers) nor is it a necessary logical progression of such arguments, I think. You're talking about showing the boring parts, but I don't think that's really the same as having characters other than the true love show up first in the story. There's nothing about interacting with love interests that you don't eventually end up with that's inherently boring. If you consider comparing it to real life, very few people sleep or go to the toilet because it's interesting and engaging, and while you could make an argument that they do walk for that reason, I think the appeal of that is mostly physiological as well. But plenty of people interact with the opposite sex for purely recreational reasons, both in a romantic or sexual context and otherwise. I don't really see this as equivalent.
if you start allowing characters to do anything even if it's out of the genre, then the whole thing collapses. you do see people complaining "why didn't the characters do <thing X>" when "thing X" is the type of thing which would clearly derail the entire type of story it is.
When that happens, I think it's generally a matter that the audience members have failed to put themselves into the emotional mindset of the characters or (and this is fundamentally the same thing) the studio didn't do an adequate job of conveying that mindset. More rarely, it could be a case where the character realistically wouldn't have thought of the solution to the problem. Often, things that would derail the genre are a variation of the former version, where members of the audience see that a problem could be solved by being ruthless or callous, and then character action could indeed be attributed to genre, but it's more accurate to say that it's a realistic moral human behavior. But when there's no reason for a character's actions besides "that wouldn't fit the genre" (and this isn't something I can think of an example of anyway) then that seems like a poorly composed plot.
(lots of stuff, snipped since I'm not addressing specific bits)
I agree with the general thrust of what you're saying but notions of "how much chemistry they have" and "how well the character was developed" aren't really things that can be addressed in as concrete a way as you're implying, I feel. It's not like you could tally up instances of interaction and rate them on even a subjective scale and get something meaningful, if you were observing real-life relationships. Like, even though a lot of people may disagree, I think that the Re:Zero anime did a good job of something a bit like what you're complaining about, where there was interactions and time spent with Rem, and even though there was less going on between the "main girl" and Subaru for most of the show, it still felt believable that he was attracted to her and simply wasn't to Rem. Not as extreme as you're construing for the Danny Phantom thing, since they did have something going on, and I don't think this may be more of a clarification than a contradiction, but that's just a point about attempts to measure such things.