It isn't like VW is much behind Tesla in EV sales: 171k BEV plus 171k PHEV vs. 386k for Tesla in H1 2021, and VW had faster EV growth than Tesla compared to last year.
I suspect this is more about interoperability, e.g. a charging station deal or something similar.
VW is a far larger company, including when it comes to sales networks, distribution networks, and manufacturing. If there is any scenario - looking out a decade or so - where they don't always outsell Tesla in EVs, it means a horrible disaster has befallen VW as an operating business.
Given the size of the global automotive industry and the major players, most of them will end up outselling Tesla in EVs. It's an inevitability. And it says nothing inherently about who the best EV makers are (that goes for Tesla as well). Plenty of mediocre vehicles get sold in volume every year (just look at the garbage sedans GM and Ford produced for a couple of decades).
It is signal when management brings in the competitor’s CEO to tell you what you’re doing wrong.