Also, it depends on the opportunity cost. It's great to think you're such a great guy that any employer will pay anything to have you, but that's simply not true for most people. If you're losing out on a major grant or bonus, that could be far more than the new employer is willing to pay. I know because I've been in these situations, on both sides of the table. If we budgeted $500k for some job, you're not getting an extra $250k just because you'd about to get that in two months if you stayed with your current employer.
And no new employer can compensate you for the right to mention on your resume that you completed a major project you were 6 months from completing when some criminal decided to harass you.
People can also decide to pass on deferred compensation when it's not "life changing money" as I heard one individual express once when he left behind some pension or stock or whatever the carrot was that was held out in the nearish future at a previous company I was at. Basically end this deferred compensation for the promise of a better one albeit with a later maturity date.
Lots of calculus and variables involved in these situations obviously but it never hurts to ask and align on these sorts of things where possible. Folks usually don't get mad when others act in their best interest, they'd do the same if they were in the others shoes is how it seems to me.
