We punish people all the time for non-violent, white-collar crime; often very severely. Bernie Madoff got sent to prison for 150 years and died there and, as far as I know, he never solicited a murder for hire.

If a Mafia boss never strong armed a merchant, never busted any kneecaps, and never pulled a trigger but simply paid other people to carry out various crimes, should the law give him a short sentence because he was non-violent?

I don't know what the appropriate sentence for Ulbrecht, but I think your claims about proportionality are missing the fact he didn't just direct commit a few crimes, such as trying (unsuccessfully) to hire a hitman, but he facilitated hundreds of thousands of crimes. Maybe you think selling drugs and guns to randos should not be illegal, but that is a separate question of whether or not he broke the laws as written.

As for your last point, I don't disagree that the wealthy/powerful/connected live under a different justice system than everyone else.

"Actual murderers get out in less than a decade" is a reason to put actual murderers in prison forever, not to let everyone else out even sooner.

Wasn't silk road selling way more than just drugs ? Like, pornography and gun, worldwide. When you facilitate both sex trafficking, organized crime and potentially terrorism you can't exactly be surprised you get hit with everything.

I once noticed (in the UK) that two people who I read news stories about in the same week got similar sentences. One for breach of copyright, one for sexually assaulting a teenager.

That said, I think Ross did knowingly enable violence?

Yeah, but in that case, we should pardon all people convicted of drug possession or distribution, not specifically Ross.