TOS was cancelled before many of us were born, so I don't think the idea that it was a "failure" applies to today. From what I understand, TOS was a huge success in reruns and that success is what ultimately led to the cast's return. So time and circumstances after the fact wash away how TOS might've been perceived in the 1960s. If they wanted to get as far away from what TOS and ENT were, they wouldn't have made DSC a prequel and they wouldn't have integrated any TOS characters into the series. What they would've done is make the Picard Series right off the bat. You could argue that they revisited the TOS Era (no matter how it looks) because of the Abrams Films, but even then: when it came time to reboot the films, they didn't reboot TNG, they chose to reboot TOS.