End of year 1: job A $100k, job B $60K
End of year 2: job A $200k, job B $180K
End of year 3: job A $300k, job B $300K
Of course if it's a startup, the odds are high that it would fold within three years. So unless it's a BigCo job that you are planning on sticking with... it's tough for me to make the argument that it's worth it to walk away from a decent but non-ideal offer. Employers know this and use this as leverage against you.