We must figure out a way to extend the lives of dogs. It's not their fault that evolution gave them a short life span.
Scientists should try to achieve life extension for as long as it is possible. Whether that is just to raise the average lifespan a couple of years, to 200, to 1000, or to eliminate aging entirely and give everyone an indefinite lifespan.
Considering that technological advances typically do not happen in isolation once we've discovered how to raise our lifespans chances are good that technology will increase in other ways as well, so we'll have plenty of food and overpopulation won't be a problem.
Even if overpopulation did become a problem the way to deal with it would be for people to stop making babies, enforced by the government if necessary. While I'm not ordinarily for the government intruding on reproductive decisions intruding on whether people can have babies is less intrusive and less denying of freedom than intruding on how long people can live. So if we had to do one or the other to prevent overpopulation I'd prefer restricting reproduction.
So much time is wasted by death, mostly because the time it takes to educate people to a competent level in any discipline is about 1/3 of their life. Massive scientific advances could be made if people could spend 4 times as long as they currently can doing their research.
Before science makes attempts to extend human life expectancy we must address issues of overpopulation on the Earth. The resources of Earth would not be able to handle the resulting increase in the world's population if we extended human life expectancy to 200 years, from the current 71.0 years. The issue of food alone is overwhelming, housing and natural resources just add to the mix.
No, people as it is are already living so long that we can not take care of them all. The world population has grown to large for the earth, and if we lived that long there would not be enough resources to feed and provide shelter for everyone on earth.
I think it would be wrong for research to specifically aim for an exact age. However, from what I've seen so far, 200 appears to be the magic number that life extension researchers are looking at. I doubt they'll reach it in my lifetime, but we will see many benefits from their efforts in years to come.
While I suppose in the future science may make it possible to extend life to the age of 200, it is obviously not near being possible at this time. Extending human life is obviously possible and we improve with each succeeding generation, but making this leap forward will more than likely happen slowly.