An argument I would make would be for future proofing your employability. You clearly care about thinking long-term. What if the current gig goes under, are you

An argument I would make would be for future proofing your employability. You clearly care about thinking long-term. What if the current gig goes under, are you properly trained in technologies other companies in 5-10 years would use, that maybe your current gig doesn't? Just spitballing. If you really are 10/10 happy, and aren't concerned with the possibility of that company blinking out of existence and being screwed, I would probably just say ride with it until you feel like quitting.