Yes it is based on an assumption you work for a _legitimate_ employer and not some shady consultant. I'll use your statement to prove that it's a fair assumption in the average case.

> So, say I set aside 1 year for the new employer to get all the internal budgeting approvals and initiate my GC process

On one hand, you claim that it takes a year for the employer to get your GC going. And now to withdraw it (which will include the same filing fee + lawyer fees - time spent= thousands of dollars) it takes them less than a month (or few months) to budget this?

No proper company would want to spend another penny on an outgoing employee. And this is a completely sane assumption. You can choose to disagree, in which case I'm sorry to say, you're paranoid.