[Tyrannosaurs]

Interestingly I think the one thing that would cause a spike happened outside the last two decades - the discovery / development of antibiotics.

You may be right but there will still be bottlenecks in the process around patient trials and the more "manual" stages of any treatment.

I think the next big improvement will likely not register on life expectancy because it will be in response to a specific problem. The next generation of anti-biotics for instance will have a massive impact but will likely only cancel out the negative impact of drug-resistant strains of bacteria.