It's a lot of work to sort out what an instructor wants out of you in the early stages. A different instructor can upset the applecart and deal a serious setback to a building and still fragile self confidence.
And yes, there's a lot to learn and every instructor will have a different approach to what needs to be emphasised now or left for later.
On the instructor's side, every student can present new ways of getting the airplane bent or worse. It takes a while to learn what a student can be trusted to do reasonably and where extra vigilance is needed.