It's hard to quantify a house speaker's job as having major achievements since many of the bills they support often get watered down after they leave the house. In Pelosi's case, a majority of Dem congress people are going to support her because of her experience and her ability to deal directly with Trump (who oddly enough seems to not dislike her). So let's say the Dems want to get an infrastructure bill through the congress next year (something Trump also happens to support) then having someone who can do business with him to negotiate the finer points wouldn't be a bad thing. All things said however, I think the Dems need to start transitioning away from these aging career politicians and towards newer faces who are reflective of the new Congress.