I get the point that everyone is making, including the point that you're trying to make. But if I just take your question at face value, isn't the answer simple: from billions in profit they make per quarter.
So you want to drain your profit to match the salary? I would think it would cause issue with the shareholder and when you want to pay for other future non salary expense, but fine lets ignore that. But what if China simply offer more salary again ? Remember, china has way more money than TSMC or even the whole Taiwan.