I really wonder (perhaps suspect) if getting renewed for season 10 wasn't as much of a sure thing as they made it seem. I think maybe they went into the season, or part of it, thinking it could be the last. That's why everything, up to a certain point, really looked like they were gonna be wrapping up Buck's "happily ever after", most likely with Tommy. Same thing with Eddie.
And then, shit, we have a whole other season now that we have to drag this shit out.
Anyways, whether that's true or not, I really feel like the show is on its last legs and it'll take a LOT for them to get season 11. Far better shows have been cancelled for a LOT less. (RIP Brilliant Minds 😭)
I'd kinda wondered that myself, honestly. There was a lot this season that really seemed to fly out of left field at the end--like, even more so than usual, and I was quite surprised by some of the directions they took. Like, honestly, a lot of the threads they ended the season on could have functioned pretty well for a series finale.
And I agree, I don't think season 11 is much of a lock at ALL. Particularly if Nashville doesn't pick up in the ratings. They both seemed to be pretty steady in viewership, but I feel like I saw a lot of commentary about Nashville not doing very well in the "demo" audience at all--or at least not well enough to justify the expense of making it. Sure, they're saving money with TN tax benefits...but they also have multiple cast members that are NAMES, even if they're not as big as Angela Bassett or Jennifer Love Hewitt.
Like I said, I think the Theo situation will likely cover a lot of ground next season as far as Buck's personal storyline. Be interesting to see which direction they go with that.