I feel like most people at most jobs are just bullshitting their way through the day and hoping no one finds out.
In a way, yes. Because in "most" jobs there are very few concrete skills that you need to know in order to succeed.
I've done heads-down software dev work, I've done software sales and marketing, I've sat on the board of directors for startups, now I've done criminal trial work, I've done civil trial work, I've been a tall-building-lawyer, and all sorts of other things.
Keys to success in all of them:
1> get organized and stay on top of tasks and deadlines, DO WHAT YOU SAY YOU WILL DO.
2> express yourself well and ask good questions, understanding what someone wants is (duh) the key to giving it to them. I don't care how smart you are, if you don't know what the other person wants (and you can only get that by talking to them and having a relationship with them) YOU CAN NOT PRODUCE IT.
3> do what you can do and ask for help when you need it. But try to as self sufficient as possible, at the same time don't bang your head against the wall with things you can't do. Fine line to walk.
Whatever super tech skills you might need are honestly secondary to those listed above. All the successful people at any company are going to either be technical geniuses and therefore given a wide latitude on social skills/eccentricities (rare) or they are going to be masters of the above skills.
So in a way, you're right. People are BS'ing their way through the day, because the skills you think are important (knowing every tech detail by heart) aren't that important.