There is a big difference between the undesirability of skiing and the inability to ski at all. With both Epic and Ikon passes, there are many mountains to choose from and snow making is quite common which means that even in a terrible snow year pass holders can find somewhere to ski.
Because my children and I compete in other sports, my family almost never skis until March or April. For someone who prefers skiing black and double black runs, there many not always be options to challenge one's ability but there should be an opportunity to ski at one of the included resorts in March and/or April. My family has skied many times at Whistler which closed on May 27 in 2019 and was previously scheduled to close this year on May 25.
Although I am highlighting the difference between not being able to ski at any of the covered mountains after a certain date and not believing the conditions are worthwhile, I am not commenting on whether or not Epic or Ikon pass holders will or should refunds.