By your own reasoning, Netflix did not 'become a Netflix' by doing anything wrong.
By your own reasoning, Netflix did not 'become a Netflix' by doing anything wrong.
Browser also severely limits the bloat, mutual compatibility and privacy issues (and also Android and iOS up to certain extent). This makes technologically much easier to have a bunch of different content stores on the same device.
EDIT: I'm keeping the sentence in original comment. Valve can mess up and become a Netflix due to its own fault, e.g. if they try to use the store to primarily finance and favor their own productions. This might come to pass if they become publically traded company, as datakan mentioned.
When steam came by the distribution services were not profitable and problematic - CDs cannot be live patched, you have to print CDs to match an unknown and variable demand.
I think if Valve crashed and burned tomorrow, it'd be nigh impossible for a Steam-replacement to come and absorb the global demand in the same way Steam currently does.