Congressman Mike Honda has released an internal poll showing him with a massive lead of 57% to 13% for Republican Evelyn Li and 5% for young up and coming Democrat Ro Khanna. The district is Democratic enough that Honda doesn't need to fear Li or any other Republican. He beat Li 73.5%-26.5% last November. What Honda needs to fear is a strong Democratic challenger of the sort that beat Congressmen Joe Baca and Pete Stark. So Honda released the poll because he clearly would like to discourage Khanna from challenging him.
I have no idea what a similar poll between Pete Stark and Eric Swalwell would've shown in March 2011, but Swalwell was likely equally unknown. Swalwell didn't get into that race until late 2011. He managed to get 36.2% in the June 2012 primary, trailing Stark's 42.1%, but beating Chris Pareja, an NPP who got 21.7%. Swalwell didn't spend a lot of money to get that result, but likely did do a lot of campaigning.
Due to the Top Two primary system, that put Swalwell in a general election with Stark and no Republican on the ballot. Swalwell did spend some money overall, but benefitted because he was nearly 50 years younger and because the right and the middle disliked Stark. Honda isn't similarly disliked,so he won't have a similar advantage as Swalwell. Still, if Khanna is gearing up for a run this poll shouldn't discourage him.
Li spent $65,000 on both the primary and general election combined. So she's only going to attract the hardcore Republican voters. Any that want to beat Honda, with a more moderate Democrat, might vote for Khanna. Eric Swalwell and Gloria Negrete McLeod showed it can be done.