Are skiing lessons just for beginners?

Edit: a lot of the comments are answering the title question which is meant more as a rhetorical question. I was mainly asking the questions at the end of the post which is if it will be way harder to find a group lesson at the right skill level or if this is largely dependent on resort?

It was my first time skiing this season but I have been about 6 or so times in the past. I signed up for a lesson at Liberty and chose that I am a level 5 (can ski down greens confidently and some blues), which is pretty accurate I’d think—on easier blues I’m fine until I find myself going a bit too fast and will purposely slide down to stop myself. Anyways, I get to the lesson and tell the head instructor I’m a higher-level beginner maybe just approaching intermediate and he puts me with my instructor. We then wait around for about 20 more minutes until our group fills up to 6 people who all say they are also at that level.

Our instructor says that we are going to go for a warm up lap on the easiest green that isn’t the bunny hill since it is everyone’s first time hitting the slopes this season, which I’m fine with because I do need to get used to being on skis after a year off and I just purchased my own skis that are a little longer than what I’d usually rent so I wanted to make sure I’d be comfortable with them. She tells us to follow her and then we’ll stop halfway down the trail to discuss some stuff we can work on. When we get there I’m right behind her so she asks me if I’d be willing to stay at the back for the entire lesson to make sure we all make it down.

For the next 2 hours of the lesson, I’m in the back having to stay at the top of runs because if I start at the same time as them I’ll just finish the run or have to keep stopping to make sure I stay at the back. I’m also helping my classmates stand up when they fall and giving them small pointers. The lesson ends and we never go on any blues so I only worked on greens the entire day which I already had put in the pre-questionnaire that I’m completely comfortable with. I felt like I got nothing out of this lesson and almost paid money to work as a teaching assistant for people that had completely overestimated their skill levels.

My question is, is this how all lessons are? They’re heavily focused on beginners so if I want to do anything more advanced, like even run easier blues, I’ll have to either hire a private instructor or fully teach myself?