It was NOT 'Edison's technology' - the courts said so - and they weren't 'pirating' the technology, they were (mostly) using it legally.
They came west to escape Edison's hired thugs (it was the Age of the Pinkertons, when all the big boys hired their own private enforcers) who would 'confiscate' perfectly legal equipment for 'investigation,' beat up anyone who resisted, and often return the equipment - no longer in working condition - months later.
Please read some actual history and quit repeating Internet 'just so' stories.
Look up the history of the Motion Picture Patents Co, aka the Edison Trust, and its genesis - and don't trust any of today's Internet balladeers who love to repeat all the popular folk tales that they find emotionally satisfying. Read some real historians.
Thomas Edison was an asshole.