This is very likely what the end Brexit deal will look like. The UK paying for access to the single market while gaining relief from most of the pillars that come with it. The EU needs the UK money in it's budget and the UK needs access to the single market.

At the end of the day once negotiations start there will be a massive up front bill to satisfy those who want brexit to hurt the UK. After that there will be on going payments into the EU to allow the UK to keep what it needs and to allow the EU to maintain it's budget without having to make cuts or make members pay in a lot more.

It allows the EU to say they punished the UK and allows the UK to keep what it needs while disentangling itself from the things it wants no part of.

This leaves the EU stronger politically to move forward and leaves the UK strong as a close ally. The EU can move forward on all the areas where the UK was a roadblock and hopefully sort out some of the glaring problems it currently has. The UK leaving potentially will be the best thing to happen to the EU.