Note that sometimes the learning goal is to write a paper or demonstrate a specific skill. However, when this is not the main objective we can try to remove the barrier. 

This was also one of my biggest concerns as to whether students would be confined to their comfort zone without giving them a push. However, a change in my perspective towards this derived from a deeper understanding of the use of UDL guidelines. It emphasizes the importance of designing variability in learning and engagement by reducing the construct-irrelevant barriers and then creating desirable difficulty. Thus, the multiple means of representation, engagement and action & expression will not block learners of such needs from cognitive or non-cognitive competencies, but will, on the other hand, providing access to all learners with dis/abilities. 

I believe all the shareholders have a responsible for closing the gap in education inequities. But certainly the player that is the most responsible is the government. A good start for a change can be governmental incentives to promote the use of universal design for learning principles and then such principles could become enforceable. Like with other issues of inequality such as parking permits for people with disabilities efforts can begin with incentives then, they provoke a cultural change and finally an enforceable law can be passed to address the problem directly.