Exactly. And, most people who seriously think about extraterrestrial interstellar travel think in terms of folding space by manipulating the fabric of spacetime

Exactly. And, most people who seriously think about extraterrestrial interstellar travel think in terms of folding space by manipulating the fabric of spacetime rather than brute-forcing your way through at relativistic speeds. The latter seems clearly unattainable, while the former is simply unknown.