Because it’s never too early to spitball:
This district requires a lot of travel and basic name ID given how poor voter turnout is. That said, Salas is in a good position already representing half of the district. With Ducheny aiming for Cox’s seat on the Board of Supervisors, the field is open for a newbie to take the helm. By all appearances, Salas seems to enjoy the Sacramento thing and this extension of her career gives her a chance to do more of what she has been doing.
Which is why she and Juan have more in common that you would think; they’ve both represented the 79th AD, there’re both more pro-business that they should be given the district, and they both love “serving the public.”
Vargas has been rumored for Mayor (wanted the Democrats to ask him to do it), for County Supervisor to replace Ron Roberts (Republicans want a Democrat they can do business with but nobody wants to hire Ron should he step down) and the 79th AD (why go back when you can move up and run every four years instead of two?).
For a guy who said he wasn’t going to work for the insurance industry, then does just that once out of office, a run at State Senate makes sense. He has latent name ID from representing the 79th and running against Filner. Republicans view him as a DINO and Salas is not as solid as she should be.
Salas may be the “incumbent “ but Juan can pick deeper pockets on both sides of the aisle and has done more of the district, geographically speaking, than she has. On the flip side, Salas is a current elected, has support from Filner, Ducheny, Kehoe, Block, Frye, Hueso, Castaneda, Bensoussan, and whole host of other electeds, and can challenge Juan in the 80th AD half of the 40th SD.
The 40th SD favors Salas but Juan can easily make this competitive.