Example: Remember the Stripe Corporate Card? It was "launched" as invite-only 3 years ago and is still invite only today, with little signs of traction. Meanwhile both Brex and Ramp have become decacorns through crazy revenue growth.
It's not really just a Stripe thing either. I think people are way under-estimating how hard it is for a large company to launch and succeed with a product outside of their core offering, especially when the competition is a small nimble startup with a singlular focus on that one product.
Startups die all the time, for all sorts of reasons, but "large company started competing with it" is a rather rare one.