As to why they haven't executed and delivered a car, who knows. Could be lack of profitability at the projected numbers they could sell vs cost to bring up a manufacturing line - in addition to, as you mentioned, cannibalization of more profitable products. VW, BMW, ... etc. are they making money or just eating losses selling EVs right now?
Maybe they aren't rushing it, it is a relatively new type of "engine/fuel" for them, and they want all the kinks and gotchas worked out before they release something to preserve their reputation for reliability.
That said, just because they haven't released anything doesn't necessarily mean they can't.