I think it is a matter of timing. In the history of every country or region there is a time where one area is more prosperous and takes care of the others, then things change. Mining regions in France, Belgium, Germany used to be extremely wealthy, then the mining industry died off and the service industry in other places took over in other places. London and Scotland are rather prosperous and throwing money at Wales and Northern Ireland and you find this perfectly normal. The UK benefited greatly from joining the EU (with some help from Thatcher a few years later). The same happens at the EU level. I would argue that the UK is doing rather well, and can afford helping other countries develop. Who knows, you might need their help in 40 years.
The commission is just the executive arm of the EU. they implement what the Council and Parliament decide
My point was that currency, fiscal and economic policy go hand in hand. We can argue whether it would be unworkable and tyrannical, but I think we agree that a single currency alone can't work too well.
I disagree here. You can't expect everyone to be a car safety expert, or chemists, or biologists. When it comes to consumer protection you need professionals to assess that kind of stuff at the market level. Since the EU is a single market, that's why the EU is also the authority on this. Having a single market and leaving safety standards to each member state would be unworkable (and it's way cheaper and more efficient to have 1 institution doing it for 28 member states). Without it we might still be eating mad cows.
And when it comes to competition, no member state alone would be able to stand up to google, or apple.
When it comes to trade deals, the EU would have to firepower to impose safety regulations on Indian cars or food safety for exemple, because it is such a big market. The UK is tiny compared to China, the US, India or the EU and I would be surprised if it managed it.
The EU "gravy train" is another questionable statement. Staff costs represent 1% of the EU budget. Less people work for the EU than for the city of Paris. Well there are three main institutions. the Council consists of heads of states so they should have your interests at heart. The Parliament are people who represent you and are elected by you. If instead of voting for sensible, hard working people who could make a change, you decide to send Farage who just bitches at everything and insults people, and did absolutely nothing constructive in all his time at the EP, then it's on you. I'm not being entirely fair here. There is little interest for EU parliamentary elections and that means not the best people end up there.
As for the commission, they are like public servants in your various administrations, except they speak 2 or 3 languages. Many are experts in fields where they would earn similar or better salaries in the public sector, others could find jobs at other international organisations such as the UN or NATO. Are the salaries very high compared to national administrations? Sure. But if they were not competitive with other similar organisations it wouldn't attract anyone. Nobody wants to live in Brussels unless there is a good incentive (and you can buy Belgian beers anywhere in Europe so that's not one of them)