>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?

Why do you say withdrawal need to be done in a month? To pack-up an H1-B visa holder, withdrawal only has to be done within the 2.5 years.

Also, withdrawing I-140 is more about sending a message to the other H1-B employees to not leave. Companies are glad to cough up few hundred bucks to send that message.