Virtually all of the likely 2020 Dems have almost no national name ID, yet many of them will manage to break out and become well known once the race actually starts. Do you think (for example) the average voter had any clue who John Edwards or Howard Dean or Wesley Clark or even John Kerry were before they ran for president in 2004?
Or Bernie Sanders, for that matter?
Personally, I'd like to see him give it a go. Being the only Senate backer of Sanders's campaign is great for progressive appeal and he seems entirely uncontroversial with the Democratic establishment. If there's a good compromise candidate it's Merkley.