The vast majority of my friends and acquaintances that are in the tech industry have changed jobs with work environment (co-workers they like, friendly environment, etc.) as among the most important factors, even above compensation. That seems to be universally true of almost every developer or engineer I've come across. Work environment is a huge factor in where someone works and how long they decide to stay there or whether or not they decide to leave. Given that, engendering a friendly work environment seems like one of the most cost-effective ways to bring in and retain talented engineers.