Without AGI the path to a 2050 YES is the conventional one, and it is fully visible today. The candidates are the drugs already in lifespan trials in dogs, rapamycin (TRIAD, NIH-funded through 2029) and Loyal's LOY-002 (STAY, 1,300 dogs), plus the three in the ARPA-H-funded VITAL-H healthspan trial in people (rapamycin, dapagliflozin, semaglutide; 726 adults aged 60 to 65). The dog readouts land around 2029 to 2031; a human lifespan trial started on a positive result takes about 21 years from enrolment at 65, so the parent market's "convincing human evidence by 2050" needs enrolment by about 2029, which means the human trial would have to start on the strength of interim dog data. So the no-AGI probability is roughly P(dog trials positive) times P(a human lifespan trial launches on them within a couple of years) times P(it shows a large enough effect to be called a cure rather than a slowdown), and the last factor is the hard one: nothing has stopped any mammal's hazard from rising with age. The arithmetic with sources (mine): https://w0lph.github.io/k9/why-dogs.html?v=2

Why the path to human longevity runs through dogs

Computed from the cited life tables and trials: a lifespan answer takes 4.6 years in dogs and 21 in people; dogs share our environment and diseases, lifespan has already been extended in dogs, and a regulator has accepted lifespan extension as an indication for dog drugs.

Relevant market (maybe even arbitrage opportunity?):