Gross income isn't taxed, but profits are.
However, I do agree that the annual basis of corporate taxation creates odd incentives - if on December 31st a company finishes the year with $10 million in cash, and on January 1st they spend $9 million, they will still pay tax on the $10 million, while if they spent it just a few hours before, they would have just paid tax on $1 million.
Estonia's corporate tax system seems more sensible to me; profits are untaxed until distributed to shareholders, therefore a company can accumulate as much as needed for more long-term spending.
The $9 million in spending will be deducted for the year's taxation period of course, but that leads to the situation of the company paying say, $3 million in tax one year, then $0 in tax for the next period, which seems similar to Netflix's case as per the article.