The most important thing that leaders can do to hold onto Founder Mode is constantly and aggressively redirecting the culture to remain outcome/results oriented. In larger organizations there are often unspoken/hidden incentives or organizational structures that drive bad behavior like rewarding teams based on larger head counts or allowing goals that are outputs instead of outcomes (ship in q4 vs. increase revenue). It is easy to incentivize teams or individuals this way but it is an absolutely terrible habit to allow in your culture. Maintaining high standards within an outcome oriented culture is tremendously hard but also tremendously powerful.