When its 65-foot-tall retaining wall collapsed onto the Henry Hudson Parkway in 2005, shareholders in the Castle Village co-op were on the hook for $27 million in repairs. That trauma is ancient history, but today those shareholders are faced with rising costs that are less dramatic but possibly even more devastating. And they’re emblematic of the pressures that are squeezing co-ops and condos across the city.    Read the article………………………..