IMO Musk has the correct response that we should be looking to Mars and/or the rest of the universe to at least further our overall odds against extinction. Because you can explore and conquer other planets without pissing anyone off who wants to have babies. Exploration and science will work when politics and dictating reproduction can't.
I hate to be the one to break this to you, but no, you won't be taking a trip to Mars to see your grandchildren. See
https://dothemath.ucsd.edu/2011/10/why-not-space/ .
1) When it comes to technology how can we know if/when or how soon? Its more a case of ambition than it is engineering anyway.
2) Visiting grandchildren is not the purpose. Probability of survival is the goal.
Probability of survival on Mars... because that'd be the extent of it... mere survival. And if it is an issue of human survival on Earth being doomed, it ain't us proles heading to the Crimson hell hole.
We are hundreds of years, at best, away from a civilization on Mars (where civilization is a number notably larger than 10,000).
*explosions all around, person rushing to Musk Miracle Rocket*
A: Did you get it?
B: The seed depository was blown up.
A: Oh no!
B: It is okay. I managed to grab several boxes of seeds.
A: Able to get a selection.
B: No, just one vegetable was all I could find.
A: Well, we are going to have to live with it... these are the last samples from Earth Mars will ever get. I hope I like it, we'll be eating it almost exclusively.
B: Everyone loves broccoli.
*zoom out while rocket begins takeoff*
A: NOOOOOOOOOOOO!