Not in Manhattan though, and definitely not along my commute. Motorcycles are about as slow as the cars. There isn't room for a full motorcycle to filter through the narrow space between the row of parked cars and the line of slow-moving traffic. Hell, sometimes there's barely room to slip through on a bicycle. And it's flat out illegal for motorcyclists to ride in the bike lane.
But yeah, this is more of a special case than generally applicable to most places. On your typical suburban commute you can definitely save time by filtering between rows of parked cars at lights. That just doesn't work here very well.
And you're forgetting the double parking, bad parking, standing cars, building construction, street construction, etc. Streets of Manhattan are chaotic. Trust me when I say that there is often not any room for motorcyclists to filter past cars, especially not when bicycle lanes are present.
It being legal or not isn't the issue; it's not possible.
A minimum width lane really doesn't leave enough room to lane split. It works in places like California because they have significantly wider lanes than the minimum required almost everywhere.
That's not true. An experienced motorcyclist could filter through most US cities. Most people have no idea how small a gap a motorcycle can fit through.
But yeah, this is more of a special case than generally applicable to most places. On your typical suburban commute you can definitely save time by filtering between rows of parked cars at lights. That just doesn't work here very well.