You have a long-running obsession with the notion that the Oort cloud is a long-term exploitable resource for the human race, but you never include any articulate proposal for how this might potentially be done, even in very broad-brush terms that don't attempt to drill down to the "devil in the details" level. Sure, in principle there are abundant potential resources in the comet-like bodies that comprise the Oort cloud - there are in principle trillions of such bodies in the Oort cloud region >= 1k in diameter. Nevertheless, even the "densest" region of the Oort cloud is almost vanishingly diffuse, with extremely vast distances between one exploitable-sized body and the next, even aside from the problem of actually finding one of them. And there are countlessly abundant "devils in the details" involved with any broad conceptual scheme to exploit or colonize the Oort cloud.
Understood, and I don't want to minimize the difficulties involved. This is not a near-term goal, and the context is usually as a response to conversations involving moving to other star systems, and ideas such as the Fermi Paradox. For us, several things have to happen first: the development of portable, practical fusion power is first. Then we have to learn how to live and work and exploit resources long-term in microgravity. This means, ultimately, conquering the asteroid belt, and establishing a sustainable economy based there.
I'm not proposing some big, all-up mission to the Oort Cloud. What I'm saying is that once the above technology is developed, and there already exists a working population distributed throughout the inner solar system, that the evolution outward is inevitable, and while Oort Clouds do have their challenges, as you point out, colonizing them will be far easier and more productive than searching for the small number of Earthlike planets in the inner orbits of other star systems.
The details that bedevil us do include the ability to locate and track distant small bodies, navigating between them on reasonable timescales, energy generation that doesn't ultimately depend on the sun, radiation protection, and the actual techniques of processing the materials of these bodies into usable resources.
Most of these requirements, though, will already have been mastered in the asteroid belt, or the Trojan asteroids, or the Centaurs, or the Kuiper belt. There's no hard and fast boundary that says once one particular environment has been successfully mastered that the next one is forever closed off to us. What I am saying is that once the outer edges of the Solar System have been reached and conquered, that going back inwards towards the inner planets of other stars provides diminishing returns, and that it's between the cometary clouds of the stars in the galaxy that the expansion of life will be conducted.