I don't understand the question. Thousands of people are enjoying skiing on their multi resort pass. What are you actually asking?
Simple really. Pretty sure IKON exisits because of the Epic Pass, MCP was a way for the non MTN resorts to get into the game. Then EPIC was well....MTN.
Sure there are other, but not at this scale. They built it. For better or worse.
To the OP @marjoram_sage I have an EPIC Local (have had one since OG Colorado Locals Pass) and a MCP <- so a lot of IKON hills.
The difference to me is that everything at EPIC hills is meant to separate you from your $. I view it like a trip to Vegas. Do I prefer IKON hills? Sure, but that is because of terrain - JH, Aspen Ski Co, LCC . But to be honest, for me, skiing @ Vail is like skiing with an old friend. Call me nostalgic or whatever, but my ski season doesn’t start until my annual birthday week trip in very early Dec to Vail. It’s cold, there is generally good snow, low crowds and Holiday lights. If you can’t have a good day at Vail, assuming snow is decent, you are doing it wrong. But I’ll pay to ski DV vs free at PCMR, different strokes for different folks. And JH vs. Vail is a no brainer I’m going to WY (until I look at airfares, either $ or miles)
I debated IKON this year, but ultimately chose the path of least resistance and familiarity - a locals pass and MCP