There has been major progress with at least one autoimmune disorder over the last 30 years. Even if there has not been an outright cure, the life expectancy of someone with HIV/AIDS, who can get treatment, is far greater now.
edit: clarifying, in case the downvoter didn’t understand the combination I responded to.
I’ve never used Beeminder, but I find social commitment works well instead. Even teling someone who has no way to check aside from asking me helps a lot. That might be less effective if you’re willing to lie though.
An alternative would be to exchange commitments with a friend, proportional to your incomes...