Reality of this industry is that if you hit any hurdle at all during your career... Whether it is your own fault or someone else's, it may trigger a kind of avalanche effect because you won't display quite the same level of extreme optimism that they want to see...
Successful people in tech tend to conflate naivety with optimism and see it as a signal of capability.
Many of them have lived in a very fortunate environment where the environment rarely worked against them so they don't understand the feeling of being thrown successive curveballs, one after another while barely trying to stay afloat.
Their idea of adversity is of a hurdle that, if you can clear it, you end up further ahead, closer to your goal. They don't see it that the hurdles many people face are set up such that if you clear it, you are still behind... The prize for clearing nearly impossible hurdles is just survival.
There are things I did in my career where all the pieces in my plan fell together, amazingly, after 2 years of work and careful strategy, with full support of team members, but it all fell apart at the end because someone with power behaved in a way which was completely counter-intuitive and not aligned with their stated goals.