s-corp - huge tax liability shutting down the business based on end of fiscal year?

Hi All -
I'm sure this is a relatively common question/concern, but I can't seem to locate it on the forums. It seems like you open yourself up to a huge amount of liability just based on the dates you do business and your fiscal year. I don't believe this can be correct, but I'm trying to find the mechanism that allows you to true-up after the conclusion of the transaction.
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Simple Scenario:
Single owner s-corp. Fiscal Year matches the Calendar Year

A customer hires the s-corp to build a widget for 100k. The s-corp sub-contracts the widget out to another company for 90k. The customer pays the s-corp 100k on December 31st. The s-corp pays the sub-contractor 90k on January 2nd. The s-corp never does any additional business and closes.
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Logically, it would seem your personal tax liability should only be against the 10k you actually made. But as I understand it, wouldn't the IRS regard the 100k that was in your bank account on January 1st as taxable personal income? The following year you could show a 90k loss, but if the business is gone, that wouldn't matter, so you'd end up losing a tremendous amount of money.

This is a simple scenario, but it applies to a much larger scenario. If an s-corp is going out of business (paying last paychecks, PTO, contractors, etc), I find it difficult to believe there would be such a tremendous tax benefit for doing it at the end of the fiscal year vs the beginning of the next, and they can potentially tax you on income you never actually made, but was in your account when the year rolled over.

Any pointers on how this gets reconciled would be greatly appreciated.

Thanks!