For years, nearly a dozen San Mateo County public school districts basked in the financial glow of steadily escalating property values, combined with robust real estate sales, both residential and commercial. The net effect for those fortunate so-called “basic aid” districts was a seemingly unending increase in locally-generated tax revenues. The supply of fresh dollars was a big-time bonanza, especially for their well-paid, unionzied public employees. Other districts, which depend on enrollment increases for new money, could only watch and wonder what might have been. But those days of healthy budgetary boosts are probably ending. The current collapse of the credit markets has put a chill in Peninsula property sales. That means less dough for the basic aid brigade. The idea of belt-tightening by the Dandy Dozen is alien in these parts. In places like Hillsborough, Woodside, Atherton, Menlo Park and Portola Valley, the cascade of local lucre has been a happy given for so long that the notion of a plugged spigot will be something of a sea change. Let’s see how they react.