I have seen two types of companies when it comes to their "methods proven to work with Fortune500 companies". While everyone tends to be protective of their methodologies and ways of working, not everyone seizes the opportunity to adapt to change and evolve their way of working.
1. The armoured company. Tough, polished, well-dressed and invulnerable. These companies will say their methodologies are proven to work, and will not admit new input as long as possible. They will portray themselves as a tough player, knowledgeable, and extremely sharp. With an answer for everything, they will update their methods in long-term yearly reviews, only when business starts to hurt. This delay will make them powerful laggards, that catch up with the novelty from competitors, and often rebrand them as their own "new methodology".
2. The vulnerable company. These companies take pride in their own methodology, they know their stuff and tend to be protective of their own ways of working, but they do take in new input. They change swiftly in experimental ways, so knowing what works gets identified quick. They adapt and adopt new methodologies, technologies and sources of information, and tend to coin new terms and brand new practices according to their own learnings from the market. They are "vulnerable", open for questioning and improvements, taking new perspectives in and not intimidated by not knowing everything at one time.
You may have come across some of those. Check the concepts of vulnerable and armoured leadership here, by sociologist Brené Brown. She was in Helsinki in 2019 and her research has truly set out waves of cultural transformation across the globe. At Idean, we took a leadership course on her study, offered by Sitomo.