The DSA to the Dems is no different than the Tea Party was to the GOP in the mid 2000s. They were a hard charging, want more action for the things they believed in and eventually those candidates made their way into office. I would not say any of them made their way to leadership and in fact the Chip Roy's, Andy Biggs, Ron Johnson, etc are just mouth pieces for the GOP/MAGA party now.
The DSA are gaining steam because they are addressing working people's issues. Trump garnered those same young people talking about those issues in 2023/2024 in his populistic ways but governed the 100% opposite as most rational thinking people knew he would.
p.s. You're welcome for today's lesson.