Having done the startup thing myself, no doubt you are correct. Management and employee bandwidth limitation is a real thing in the early years. All dimensions must be optimized at once, which is an inherent paradox. So yes rapidly expand into 50+ markets and yes take enough care of dealers and after sale customer support.
In my opinion the very best companies are extremely careful about what they publicly commit to but once verbalized, follow through and do what they say with verbalized dates. Equally important during the inevitable zig-zag of startup life, communicate when those dates or why the reality must change. Do it right and you actually build goodwill during the incredible @#*#!! show that is startup life.
Ineos made strong commitments early regarding workshop manuals to support a diy ethos for their vehicle. That was a statement of value as much as anything. IMO, even more than their failure thus far to deliver on this commitment, the lack of communication has been the biggest issue because it implies INEOS is backing away from the set of values that attracted many to the brand in the first place.
From an execution perspective (and of course as a very biased observer) my inner armchair quarterback says aftersale word of mouth in their largest markets might be more important than expanding into the 51st country which likely has a tiny, tiny market size comparatively speaking. Convenient how self-serving this last observation is eh?