It all depends on the industry as well. My CTO experience was in News and Media, where software is rewritten quite often and does not have any business value by itself.
I am now in a consulting position in the banking industry. Things are different there. None is willing to take on the risks associated with technical debt repayment. It accumulates endlessly. Once it reaches a point where no local developer would work on the project, the project is handed over to Asian sweatshops which support it indefinitely.