Ask HN: Long term successful growth teams

I've worked on a few growth related teams at SaaS companies and have always noticed they seem to fizzle out after some time. Usually they are created to enhance in product education, run A/B tests, grow ARR, etc...

From my experience there is a brief time where the company is very excited about the growth team, the team is able to show great results from tests they run, etc... but then after this the team kind of stagnates and eventually is disbanded / much of the work is either done by a third party or outsourced.

I've heard of these types of teams existing at almost every SaaS type company so I'm curious if anyone has seen or been a part of one that has been able to be successful long term.