I think it is the responsibility of people pulling into traffic to do it with a sense of urgency. It’s like the people on I-5 who insist on maintaining 4 car lengths in 10 MPH traffic. Actually those people are great when you need to change lanes, you can always count on one.
It never ceases to amaze me that when my line is crawling and the ones on either side of me are moving, that I slip into another lane, and find 2-3 overly safe drivers back to back back.