I do wonder if Scott Alexander means this in the sense that he watched a few shows because Adams had died, or if there were the first episodes of Adams' shows he had watched. Dying does reveal some interesting things about a person - in Adams' case he was doing his live podcasts right up to about the end. I tuned in to one out of ghoulish interest and he seemed to be the sickest person I'd ever seen. He was clearly doing that show because he loved it.
If he had his time over, he'd probably swallow his pride and accept that It Is Not OK To Be White because of the disastrous impact on the Dilbert empire, but I do think Alexander has fundamentally misread what Adams believed it meant to be successful. He wasn't that motivated by commercial success since at least the 2010s, although he had achieved it. He seemed a lot more interested in getting ideas out there and making a difference to people's lives.