By definition they helped Trump more in WI, MI and PA. Where MI, PA, and WI would have put Clinton over 270. Have there been any cases where Republicans would have won the presidency but 3rd parties were spoilers in a handful of states? I don't think so. Maybe in 1960.
Percentage increase is less relevant with Trump on the ballot, compared with the raw votes that swung the electoral college.
I am not saying don't vote for 3rd parties. I am saying if you're in a non-safe state for your 2nd preference, do vote trading with someone in a safe state or vote for your 2nd preference who has a better chance of winning. If you vote trade, your 3rd party candidate will still get the same percentage of votes nationwide, and your 2nd preference will actually win.
The combination of mass incarceration, the racist electoral college as it is, and the the demographics of the country make it seem likely that some pragmatic and tactical voting in non-safe states will go a long way for Democrats, at least that seems to be the lesson from the past two decades. Hacking the electoral college anyone?