I was a programmer for 10+ years and I couldn't pass the technical interviews for these companies either. I started down the path of trying to self-learn Computer Science but reading books wasn't enough for me so I wen't back to school for it. Around the end of my CS bachelors I pivoted to hardware and stuck around for a masters in ECE. Now I work at one of the companies mentioned. It is much harder to learn CS on your own than it is in a structured environment.

Your experience allowed you to move toward doing work that excites you. Even though you didn't meet your goal, you still had great success.