That's not why companies don't develop Easter eggs. It's because: 1) Easter eggs are features. 2) Features cost time and money. 3) Features almost always also add bugs. 4) Easter eggs usually aren't in the test plan.

What you get is something that costs money and has the chance to decrease the quality of your software.

Now there are intangibles that make Easter eggs worth it. Mostly, you have to keep the developers happy. But don't act like they have zero cost.

Full disclosure, I shipped an easter egg in the Sun x86 service processor about 11 years ago.

I'd argue that the Tesla stuff here isn't really Easter eggs as traditionally understood; which are stuff put in by devs having fun; and then it's either not spotted or ignored by management. Easter eggs are usually somewhat hidden, and require some degree of intelligence to appreciate. The Tesla stuff is lame "fart apps" that were clearly put there under instructions by some PR guys or Musk himself. No developers were kept happy in this process.

The apps are part of a marketing plan, and I personally doubt that devs didn’t have fun building them.

My kids gleefully get to “drive” my Tesla using the steering wheel to play Pole Position. They snicker when we goof around with the whoopie cushion.

It’s hard not to be positively influenced by something that gives your children joy. I appreciate that there are these bits in the software which are whimsical that my family can play with.