The Squamish experienced poor chum runs years ago and saw closures. Chum (salmon in general) stocks are very volatile and vary a lot. We just don't understand ocean survival well at all, at least not well enough to predict and manage well yet. As chum can live longer than sockeye, perhaps next years numbers will be great. This doesn't mean we should be complacent, but its not necessarily indicative of a population crash.
Coho seem to be doing well this year. Hatchery fish are there for the taking, but they could stock less if limits were dropped to 2 or 3 fish (less competition with wild fish) which would benefit wild stocks.
I don't think reducing the limit would limit the number of beeks on the river, as a) they don't necessarily follow the reg, and b)they often fish easier to catch fish like chum, pinks and boot springs.