You can't have a telescope with that resolution. The data is simply not there, not in a manner that can be reconstructed with a telescope smaller than several solar systems at least.
I've done published research where we started by using data from a gravitational lensing search for black holes, and used data they had collected but disregarded on very distant stars. A mere 100 years ago, there was not an astronomer on Earth who could have conceived of gravitational lensing. My point is not necessarily that we will make even more ambitious and unexpected use of gravitational lensing itself, but rather, what will we invent in the next 1,000 years plus that we have no way of concieving of right now?
In that flight of fancy s/he is at epsilon eridani, so that won't be a problem (it's not the size you need, it's the baseline) :-) Anyway who cares about earth-like planets in other galaxies, this one will do fine.
The flaw in the argument is that you need one person with billions of dollars to throw at an ambitious project; of course we could also just decide to do those things collectively, and in fact have managed to do some amazing things that way.
You certainly don't need to have that scale of resources accumulated under one individual's ownership to launch massive, heroically selfless projects for the betterment of humanity. Rather, from the perspective of an individual, there are lots of heroic projects you could attack where there's no foreseeable limit to how much more awesomeness you could accomplish given more and more resources.
