Imagine if any company could just copy an indie game and scale it up/polish a bit and get all the sales.

You’re describing the entire mobile games industry. You think all those top apps in the app stores are 100% original? No. They copied other games.

Also, patents have nothing to do with that. Software is covered by copyright.

Furthermore, “back in the day” manufacturing was expensive and required huge factories to build stuff (in quantity). The barrier to entry was enormous! People were mostly uneducated and there was not much in the way of “shared engineering knowledge”. Ten thousand people could look at a car engine and have no friggin clue how it worked. That’s why patents were necessary: Disclosure

These days disclosure has become irrelevant. Any engineer can look at an invention or product and figure out both how it works and how it was made. At the very least, they can figure out a way to make it. Just look at all the Youtube channels where every day people are making complicated machines, parts, and electronics! The mysteries are gone. Disclosure is unnecessary.

Since the entire point of patents was disclosure why do we still need them?