I'm not quite so pessimistic as that. I do think it's going to take us a lot longer than people realize to become intergalactic, but as a Christian who leans post-millennial these days (but still believes pre-mil/pre-trib are possible), I do think we will reach the intergalactic stage at some point. I also leave the possibility that the Second Coming might cut that short, but I also consider the possibility that we could be around for millennia still. Then again I'm kind of in between on eschatology, so I can't say I'm certain of either coming first.
All I know is that I definitely do not believe that this planet will be wiped out by some sort catastrophic event. I am a firm believer that, whether the kingdom comes before or after the Second Coming of Christ, there is a purpose for this planet that will last for eternity. Some say I might be naive or overly optimistic, but I can't find myself coming to believe anything else.
I simply see the wonders that we already know about, and see the way that they expose glory. That leads me to believe there are future glories to be found.