Walter's ego and sense of entitlement was his downfall throughout the series, so it was very likely his downfall earlier too.
The one thing that doesn't align here for me is that all many of the scenes of Walt pre-flashback make him come across as pretty down to earth and humble, and when at the start of BB he doesn't show a hint of this behaviour until things start escalating.
How many scenes of Walt pre-BB did we see? I can only think of the one where he's listing the elements in the human body with Gretchen, and the one where him and Skyler are house shopping. Even given that, he did come off as kind of cocky in the house hunting scene. He always seemed to get riled up when he was around someone who he thought might know more than he did. Look at how he was constantly second-guessing Jesse and Mike's running of the business side of things, despite knowing absolutely nothing about that.