I mean I guess you set up a time every week and have to actually go and spend that time. I guess you would feel bad if you didn't practice what the teacher told you to?

This is what stops me progressing, I don't have a reason to play. I never progressed more quickly than when I was in a band.

But yes a skilled teacher is always worth it if you have the money. Apps, subscription services, and so on have a vested interest in keeping paying customers. Therefore they ensure you always feel safe and comfortable. If you feel too challenged, your association with the sefvice will turn negative and you'll stop paying.

But learning an instrument is not comfortable; it's extremely challenging and requires hard work and commitment. It doesn't have to be like bootcamp, and of course it's really fulfilling to watch yourself improve, but there's no hiding how challenging it is, especially if it's your first one. Good teachers know this and have the pedagogy to help you through it in as efficient a manner as possible.

Besides, the good teachers are always in demand so they are usually not too concerned about losing a student here or there because they decided it was too hard for them.

Additionally I do find it motivating to have someone else on my team helping me keep motivated with playing.