They crushed safe blue districts; the same ones Hillary won by 20-40+ points, so we definitely know it wasn't their "outsider" appeal that's carrying them along as much as it is the whole party. If they could win as just outsiders, they'd run on the Socialist party or Green party; they can't. Just like how Bernie suddenly decides he's a Democrat for exactly one year to run for POTUS before he goes back to being an Independent.

Also, it's Bernie fans who have said Bernie was virtually unknown before 2015; can't use his legacy to cover for him after he been previously cast like that. Fact is he's gotten way more support and gets way more passes because of his gender and skin color. No woman, much less WoC, would get his cult's support for POTUS.