If the EU want to make life difficult then I'm sure we'll start exporting more of our goods and services to our other friends around the world - English speaking nations, former Commonwealth states and more. As I said earlier, that's much easier outside the EU because we can negotiate a deal that works for our 2 countries (rather than them vs. 28) and relax legislation that can otherwise hamper trade. Of course, importing and exporting is often reciprocal so if we start selling a lot of financial services into Japan, for example, maybe Japanese cars become more affordable/suitable to UK drivers. With that in mind, the EU are in no position to try and stretch out negotiations as, outside of it, we'll have a whole world of trade open to us that wasn't before.
In short, we're too big a market for the EU to simply ignore or make life difficult for out of spite. Yes, it's the bigger nations that we import more from, but it's also them that pull the strings in the EU. If Estonia dig their heels in when Germany's eager for a deal, Germany can make Estonia's life very difficult.