I haven't skied Alta for as long as many, but I have been there at least once (sometimes twice) a year for the last 4 years. We plan to go back this season also. We just love it there (we all like ski areas, not resorts.)
Personally, I love having snowbird next door. It gives the boarders a chance to 'ride' LCC powder. I LOVE, repeat, LOVE having no boarders at Alta. I don't care if they raise their tickets to $70, I would rather keep 'Alta is for Skiers', and I have told that to every instructor, management person, and ski patrol that I come across. I don't know how long it will last, though.
I think Alta has a loyal local following that will keep it going. It is a Utah institution.
I don't think it is the facilities that caused declining visitation. It's the snowboarder ban. Many families have kids that board, and won't go there. I think a mixed group of adults is fine, with the combined ticket, but people don't want to put the kids at snowbird ans ski Alta themselves. It is too far.
I like the facilities the way the are. They don't run the high speed lifts at full speed, and there is no development at the base - love it all.
Alta just has the best 'soul' of any mountain I have been to. Any of course the best snow year after year.