Humanity will never put effort into this. We don’t have the technology yet but yes we can develop it but doing this is harder than building a bridge across the ocean between Asia and the US.
That bridge is also within our technological capacity. But it’s not happening period.
That depends on the scale of human society, doesn't it? Grow the population in the solar system enough and it becomes a smaller fraction of gross output than many trivial and frivolous things are today.
I'm arguing here that if non-interstellar space colonization is possible, interstellar colonization is a natural and feasible extension. You might argue that even colonization in the solar system will not occur, and I admit that's a defensible position.