I take great exception with your points about the Space Agency involvement. Not to say it's an In/Out point as such, I am sure we could remain involved as an Ex-EU member.
However, space agencies, exploration and scientific investment is fundamentally a profitable thing to do!
Political - it unites countries (see Russian involvement with Europe and America despite the numerous other tensions)
Economical - it provides jobs, including some here, not only in the "now" but also the technological and processes developed go on to provide support industries and whole new industries entirely - we're beholden to the American / Russian space race for so much of our industry (and thus economical stability)
Social - the above unification of communities and people, the breaking down of barriers, the ideology of learning, the inspiration of the young to look at STEM jobs as a career (without with we're :censored:ed, frankly) and more besides. It also grows our understanding of the universe from which only good can come, because if humanity's history has shown anything it's that we're not content in one place, we will continue to expand - it's in our nature.
Technological - A list so long it has multiple wikipedia pages and I couldn't even begin to list them here: https://en.wikipedia.org/wiki/NASA_spin-off_technologies(and these are just the primary ones for NASA, there's multiple other agencies and additional spin offs from the spin offs).
Sorry - you hit a nerve, the rant isn't specific to you!