Yes but compared to the size of their economies - let's keep it simple by looking at the GDP - the UK would be hurt disproportionately more. The UK GDP is ~$2.5 trillion, the EU GDP (sans UK) is ~12 trillion.
Why do most Brits still assume the UK is a large market compared to the rest of the EU? The UK is no longer the empire it used to be, it is weak on it's own. The UK GDP is about ~$2.5 trillion, the EU GDP (sans UK) is ~$12 trillion. The UK economy is puny compared to the mainland Europe. I very much agree that a good trade deal would be beneficial for both sides, at this point the EU is under strong pressure to make an example out of the UK secessionist tendencies and the power is squarely on the European side.
London is perfectly fine on a 50k salary, provided you don't try to keep up with people who earn 3-4 times as much. It sounds to me that she was on an entry level or clerical/secretarial position (nothing wrong with that), but that's not what is usually associated with people who work in finance. The solution there is not necessarily to move out of London, but simply realize that in banks in London you are going to be surrounded by people earning >150k (and often much more) and there is no point in trying to keep up with them on a 50k budget.
You provide zero evidence that the US stocks are overvalued (I'm not saying they aren't) so you should refrain from demanding evidence from others.
Furthermore, why do you think the FED should've raised raters earlier? Supporting the stock market is not their mandate and it is thus not directly relevant whether and how long has the current bull market lasted. A big market crash just a few years after 2008 (and 2011) would've certainly had a dampening effect on recovery so they might have felt justified in increasing the money supply. Inflation is running low, economic growth and labor markets were very weak for many years after the 2008 crash. They had pretty good reasons to be supportive.
Ah the good old days of worry free high school chemistry/physics classes. My chem teacher poured out a pint of mercury and allowed us to push our fingers into it to feel how different it was from liquids like water. Good times.
Did you actually read my post? If yes, can you seriously not see the difference between writing/testing an OS and writing/testing the software that controls jet engines?
Open sourcing something like Linux works very well _precisely_ because it has a very large audience and is (relatively) approachable by hobbyists too.
On the other hand, aerospace engineering and software is narrowly specialized with a (relatively) small group of experts and code used in commercial/military aircraft is anything but approachable to hobbyists.
Then there is the fact that unit testing this kind of code requires engineering knowledge of the specific hardware involved (e.g. not just any jet engine, but one very specific model). Finally, let us not even mention the huge pink elephant in the room, namely that the absolute and vast majority of "hackers" does not have access to jet engines used in commercial (or military) airplanes and even fewer have the ability to conduct test flights.
While I agree with your statement that open sourcing code can help with improving it's quality, how exactly do you envision (paraphrasing) "hackers contributing pull requests" to code that controls engines on an airplane? Here you have an extremely specialized codebase which can perhaps be understood by a tiny group of professionals and it can actually be tested by an absolutely vanishingly small group of individuals under special circumstances. I don't think "hackers" could even begin to make useful critique of this kind of software, let alone contribute pull requests to it.