Exactly, if we were to listen to such tales (or similar ones by penny pinchers), we would still be hitting rocks to make fire in our little caves. Venturing beyond is an amazing way to enrich our knowledge graph.
So I believe that there is an argument to make that insanely expensive, hard, and pretty much useless engineering projects (w.r.t. solving the biodiversity problem, which is actually about survival on Earth) could possibly be questioned.
Some will say that "if you don't spend all that money into inhabited space exploration, you won't necessarily spend it wisely. But I would disagree there: we should really start spending money (and fossil fuels) wisely because we are running out of time.