Re: Brexit just gets better?
This is why a Deal is so important.
Of course a deal is important, to both the UK and the EU, if it's a good deal with reasonable compromise on both sides. Your discussion above is a little ingenuous, not least because tariffs on imports to the UK will of course hit companies like BMW, Audi, Mercedes, etc. through a drop in sales. It's in everyone's interests to negotiate low tariffs in both directions, and that is, after all, the main purpose of the WTO. Also note that imported components which are later re-exported in finished products will likely not be subject to tariffs, which further changes the calculations.
The chances of the EU agreeing to such a deal pre-Brexit are fairly close to zero, though, because that would mean them trying to make Brexit work in good faith, and that's politically very difficult for any EU politician. This is why we've got Theresa May's appalling sell-out deal, it's all the EU could ever offer.
After the Brexit dust settles, when all these negotiations go back to being shady negotiations between civil servants in back rooms, and not on the 6-o'clock news every night, I'm sure many workable deals will be done that will save face on both sides. That's what politicians are best at, especially when lobbied by industry.
In the absence of (an impossible) fair deal up front, it's far better to have a clean no-deal Brexit with full freedom for post-exit negotiations than to accept a bad deal for the UK which the EU will then simply refuse to change in any way.