Manufacturing was dealt a heavy blow long before MT came to power whereby a failure to invest coincided with a large expansion of third world industrial output on the back of cheap labour costs and the added bonus of starting with up to date facilities. Globalisation became an issue from the 70s, whereby goods produced with a fraction of the labour costs here were able to undercut indigenous manufacturers. All political parties are guilty of failure to have a coherent policy addressing the issues. We further shot ourselves in the foot with the terrible industrial relations in the 70s and early 80s. Thatcher came to power on the back of a workforce relation situation perceived as verging on anarchy. Whilst it may have only been a relatively small percentage of the workforce involved, it inconvenienced most people. The striking workforce put MT into power.
The definition of state aid is far reaching and at the mercy of the lawyers. It is impossible to imagine the state setting up any enterprise that wouldn't have some competitive element subsidised. Any subsidies given for whatever reason will free up cashflow for use elsewhere - i.e subsidised by the back door. Infrastructure is state funded at the expense of direct industrial investment, because you can't build a bridge for example with state money and then export it. It is safe and uncontentious. Think of what the projected cost of HS2 could buy in terms of manufacturing capacity.
The motor industry is under pressure from all sides, of which Brexit is but one reason. Global warming has struck a chord in many countries, with diesel sales way down. Ultimately it is consumers not buying so many cars for a range of reasons, both here and abroad such as China. Germans arent' buying so many BMW, Mercedes and Audi cars either, and they will have virtually no UK input. Different reasons, different locations, same outcome.
We have a huge trade deficit with the EU, or more specifically the Eurozone. I cannot see any way to address the lack of competitiveness with German output, which is the main source of the deficit, because the undervalued Euro in terms of the German economy effectively subsidisies their industrial output, as has been discussed several times previously. Of course it isn't state aid because the Euro is a currency basket, but it might as well be. The EU made the Eurozone, nobody else did. Having to adhere to identical rules ties our hands, but leaving would allow us to tweak them a little to best suit us. However, the biggest opportunity to address the imbalance still lies in the hands of the consumer.
Both sides do indeed need each other, but only today Spain rattled its cage by insisting Gibraltar is a British colony and documented as such. France wants to fish our waters as do the Spanish. Every other country will (rightly) push to get whatever it can from future negotiations. The position we would be in if May's agreement was accepted would result in the EU giving everyone what they wanted at our expense in return for us to have whatever access they would allow. TM raised the white flag by accepting such a weak position. Yes, we opted to leave, but she has given us no hand to play in the future. BTW, I don't have a problem us paying for contractually agreed contributions as long as we get a rebate for our not benefiting in the future, and the EU continuing to honour UK payment contracts already placed.
Like everyone else, I don't know what the immediate future holds. I really cannot see the agreement giving us any leverage whatsoever, and at great cost to boot. There is absolutely no point in being tied to the EU with them setting all the rules and us paying for the privilege. It's a halfway house that suits nobody. At least with full membership you have a say for your money, though I suspect that option will expire after the 29th March even if the date is put back with current terms no longer applicable. Reapply and we might well have to join the Euro. Anyone? The situation is farcical, we have to bite the bullet and leave properly, and immediately find a bunch of politicians capable of making it work. TM has to step down on exit, so that someone can do a proper job.