The claims are "extreme" because you don't like them, and the confidence of astrophysicists in this matter is a consequence of the overwhelming weight of evidence.
You have decided to take a position on a subject you are completely ignorant of, and that contrary positions to this are "extreme" and thus must be treated as fringe nuttery. Essentially, you think that your ad hoc guesses should be treated like the null hypothesis. You can try and dress it up in as much intellectual sounding language as you like, but you are being absolutely moronic and I'm done with you.
All governments prop up their launch industries. Yes, this includes the US government supporting SpaceX: they wouldn't have made it through their early difficulties without NASA support. Elon Musk readily acknowledges this, its more his libertarian fanboys wanting to hold up as some paragon of the all-conquering private sector.
That said, Ariane 5 is now looking a bit subsidy heavy, despite it being a very commercially successful launcher for years. This is why they are trying to make Ariane 6 much cheaper. If this doesn't work, or rather can't be made to work without an unacceptable subsidy, ESA really needs to look towards Skylon.
Although you make the common error of thinking that the only requirement for dark matter is galaxy/cluster dynamics, you have stumbled on an interesting question; why is the Milky Way dynamically dominated by dark matter but the solar system is not. Fortunately, its easily answered.
Dark matter makes up most of the mass of galaxies, including the Milky Way. One of the best bits of evidence our own galaxy has dark matter is the rate at which M31 (Andromeda) is approaching us. The expansion of the universe drives galaxies apart, so the combined mass of the local group (basically just us and M31, M33 is next in mass but its much smaller than M31) has to be enough to pull the two galaxies together such that you would see M31 at the present distance and velocity. This is called the local group timing argument, and it shows that there is much more mass than can be accounted for with visible matter in the local group. This is not the only evidence for dark matter, but it along with the milk way rotation curve makes us confident that there is substantial dark mass in our galaxy.
As to the reason you don't see much dark matter impacting on the gravity of the solar system: that comes down to geometry. dark matter is arranged in a spheroidal halo whereas most of the visible matter is in a thin disk. The dark matter halo is much less dense in our galaxy than visible matter (and especially so in our solar system as for obvious reasons its got a higher density than the galaxy as a whole) but for large enough $r$, proportionality to $r^3$ always wins out over proportionality to $r^2$, which is why dark matter dominates the outer part of the rotation curve whilst at the same time being irrelevant for the internal kinematics of our solar system.
A lot of engineers and computer programmers seem to think that dark matter is just a fudge to make rotation curves fit, and that they being smarter than astrophysicists can see through this obvious error. This is profoundly irritating
Dark matter is required to explain the ratio of elements produced during big bang nucleosynthesis, the acoustic peaks of the cosmic microwave background, gravitational lensing, cluster dynamics, the Local Group timing and finally, yes, rotation curves. In the last application (which is bizarrely considered to be the only place dark matter is invoked), the most popular alternative hypothesis MOND, which has no theoretical basis and exists purely to fit rotation curve data, doesn't actually do that well on modern rotation curves.
You cannot offering any critical comment on dark matter that won't make you sound like a terminal case of Dunning-Kruger to an astrophysicist unless you understand all of the things I mentioned above.
Dark matter is NOT a kludge factor. You should not make such strident pronouncements about a subject you clearly know nothing about. The existence of dark matter is not controversial amongst astrophysicists.
The fraction of deuterium produced by primordial nucleosynthesis, and the ratio between the acoustic peaks in the CMB, both require ~83% of the mass of the universe to be something other than baryons. Given that these two indicators are from entirely separate epochs (about a hundred seconds after the big bang for the former, and hundreds of thousands of years for the latter) this is a strong result.
"Life begins when you can spend your spare time programming instead of watching television." -- Cal Keegan