>I have seen speculation that medical advances will increase
>life expectancy to 140 or 150. My question is will it be
>proportional or will people just stay 80 for 70 years?


There's an actual reason why people don't live longer than 120 years. It has nothing to do with bodily health. It has to do with the other components of our being, for we are (1) soul, (2) spirit and (3) body beings, made in the image of God, in His likeness.

God decreed 120 years max for man after the flood. Prior to that humans lived as many as 969 years, many over 900. We were also bigger then, much larger than today, as were the animals of that time period before they died in the flood. The giants of old remained after the flood, in the days of Noah. It's possible Noah was a much larger man than we see today. Many Egyptian writings record large people living alongside smaller people. It was always assumed this was to represent status, but perhaps it was literal, as the Bible declares as below.

There is this whole set of knowledge which has been lost in our "modern societies" that is there for all to understand. These truths God told us have been supplanted by lies from the enemy, who doesn't want us to know about the reality of our situation, but wants us deceived so we won't go back to God. It's very cruel what's being done to men around the whole world. And the glory of what God has in store for those who will hear the truth ... it's just amazing, and deserves some paying attention to.

Genesis 6:3 - KJV - "And the Lord said, My spirit shall not always strive with man, for that he also is flesh: yet his days shall be an hundred and twenty years."

And on giant people:
Genesis 6:4 - KJV - "There were giants in the earth in those days; and also after that, when the sons of God came in unto the daughters of men, and they bare children to them, the same became mighty men which were of old, men of renown."