People sometimes believe it isn't possible to be creative, engaging, and accessible all at once. This has not yet proved to be the case, and arguably there is little more disengaging than finding you cannot learn about the topic you want or need to.
They also think accessibility is too difficult or time-consuming, especially for potentially complex systems like LMS. Like most other things we learn to do during our lives, accessibility seems difficult at first. There are new skills and techniques to learn, and until they become familiar, they take a bit of extra time.