As VP of Prime Gaming at Amazon, we failed multiple times to disrupt the game platform Steam. We were at least 250x bigger, and we tried everything. But ultimately, Goliath lost. Here's why: The 15+ year long attempt to challenge Steam started before I was VP of Prime Gaming, but we never cracked the code. Not under my leadership or anyone else's. The first way we tried to enter the online-game-store market was through acquisition. We acquired Reflexive Entertainment (a small PC game store) and tried to scale it. It went nowhere. Then, after buying Twitch, we created our own PC games store. Our assumption was that gamers would naturally buy from us because they were already using Twitch. Wrong. Finally, we built "Luna," a game streaming service that let people play without a high-end PC. Around the same time, Google tried the same thing with their product "Stadia." Neither gained significant traction. The whole time, Steam dominated despite being a relatively small company (compared to Amazon and Google). The mistake was that we underestimated what made consumers use Steam. It was a store, a social network, a library, and a trophy case all in one. And it worked well. At Amazon, we assumed that size and visibility would be enough to attract customers, but we underestimated the power of existing user habits. We never validated our core assumptions before investing heavily in solutions. The truth is that gamers already had the solution to their problems, and they weren't going to switch platforms just because a new one was available. We needed to build something dramatically better, but we failed to do so. And we needed to validate our assumptions about our customers before starting to build. But we never really did that either. Just because you are big enough to build something doesn’t mean people will use it. Reflecting on these mistakes, I realize how crucial it is to deeply understand customers before making big moves.