I think even claims of 2-5x are highly suspect. It would imply that if your team is using AI then all else equal they accomplish 2-5 times as much in a quarter. I don't know about you but I'm certainly not seeing this and most people on my team use AI.
[And to those saying we're using it wrong... well I can't argue with something that's not falsifiable]
My company is all in on LLMs and honestly the improvement seems to be like 0.9x to 1.2x depending on the project. None of them are moving at break neck speed and many projects are just as bogged down by complexity as ever. Pretty big (3000+) company with a large mature codebase in multiple languages. For god knows how much money spent on it
Once a company gets to a certain size, they no longer optimise for product development, instead they optimise for risk mitigation. A lot of processes will be put in place with the sole purpose of slowing down code development.
[And to those saying we're using it wrong... well I can't argue with something that's not falsifiable]