The Noe Valley Community Store is gone. So are Seeds of Life, Ma Revolution, Red Star Cheese, Uprisings Bakery and dozens more Bay Area food collectives birthed in the 1970s. Rainbow Grocery, however, is still here. As the collectively owned grocery store turns 40 this month, Saturday lines at the cash register can still stretch back into the aisles, and its bulk bins are refilled with the urgency of Muni N cars during rush hour. The store just paid off its mortgage and invested $3.1 million in massive renovations. Not that the store’s 243 owner-workers believe that present-day success guarantees future stability.