The very reason you're expected to die in your 90s is that your body has decayed into a complete mess where nothing works properly anymore and every single capability reserve is at depletion. You die in old age because if you spend long enough at "one sliver away from the breaking point", statistics make going over it inevitable. Even a flu is a mild inconvenience to the young, but often lethal to the elderly.
To make it to the age of 150, you'd pretty much have to spend a lot more time as a healthy, well functioning adult.
Everyone keeps talking about health care but IMO it's really downstream of you attending yourself. It's almost a spiritual thing really. American health is so bad because Americans don't feel like they themselves are worth taking care of. The contrast between the people who disagree here gets extreme as they age.