What is the point of our lives, what is the great commission, and do "people groups" have special significance? (Matthew 28:19-20)

It feels like I've asked this before, but since I believe it was not avail here it goes again.
I'm really annoyed lately by some friends of mine who are die hard believers that:
1. The point of our lives is to fulfill the great commission
2. The great commission will be complete when there is someone from every "people group" who is a believer
3. Then the end will come - and this is a good thing.

My thoughts are this:
1. The point of our lives is to live a life of enjoying our savior and creator. This will include fulfilling the great commission.
2. The great commission is to preach the gospel to EVERYONE (that is, ethne in Matthew 28 means EVERYONE, not "people group" in whatever way we may describe that, but any people group is made up of PEOPLE which are included in EVEROYNE).
3. None of us have any idea when Jesus will come back, we cannot "bring it about" by seeing if we can get one believer in each "people group." And it will be a good thing when it happens, because God will be ready - not we've made Him ready.

Am I missing something? Is there a good reason for the Joshua project if this is the case?

Now don't get me wrong, some people have a heart for unreached people groups. Great. Go get em. EVERYONE needs to hear and how will they hear if we don't tell them? But that doesn't mean evangelism to a small tribe in the mountains of central Asia are more important than your neighbor Joe (unless God calls you to said tribe). God loves people. God wants EVERYONE to know Him. Not just every language so the songs in heaven are pretty enough.

Help me out. What do you think?

"Go therefore and make disciples of all nations, baptizing them min the name of the Father and of the Son and of the Holy Spirit, teaching them to observe all that I have commanded you." - Matthew 28:19-20