Honestly I don't think there's that big of a material difference in difficulty between being able to (consistently) live to 150 and being able to live indefinitely (barring catastrophic accidents and intractable diseases).
I feel like we're bumping up against the edges of the lifespan that we can reasonably achieve without figuring out how to actually stop or reverse aging.
Possibly there's a world where we figure out how to dramatically slow it without stopping it, because there's some entropic principle regarding our ability to reliably lengthen telomeres where we can't replace lost data but we can reduce the rate of loss, but my money's that we don't break 150 until we actually solve aging on a fundamental level.