OK, it's not really a subway. But it is a train. And yes, it's a seven-block walk from the nearest train stop to the beach. And sure, the beach is in Long Beach.
But a train to the beach in Santa Monica could cost $4,799,999,998.75 more. And it wouldn't be ready for at least 10 years.
To get zen about it, don't change how you go to the beach. Change the beach you go to.