Because in many situations not sharing in process memory causes either horrible performance or horrible productivity. The scenario I have pretty often is in memory analysis of custom data structures with multiple clients accessing a server in a read mostly pattern.
I think your last resort suggestion is very much based on the notion that most of what we ever do is offloading all data access onto a SQL database. I like SQL databases, however unfashionable they may be at the moment, but they're not the solution to everything.
As memory gets cheaper it becomes more feasible to just keep everything in server memory and access it from multiple clients. You can't do that without dealing with concurrency issues.
I think your last resort suggestion is very much based on the notion that most of what we ever do is offloading all data access onto a SQL database. I like SQL databases, however unfashionable they may be at the moment, but they're not the solution to everything.
As memory gets cheaper it becomes more feasible to just keep everything in server memory and access it from multiple clients. You can't do that without dealing with concurrency issues.