Many replies here argue that there are plenty of choices today for the hacker-inclined, many more than 40 years ago, which is true, of course.

But I think what your post implies is that regular computers back then invited you to hack them. It might have awoken a curiosity that could have otherwise remained latent in many of us.

A anecdote from the other side of the fence: Apple used to ship an app called ResEdit whose sole purpose was for you to hack with your Mac. Change strings, menu shortcuts, images, sounds. I had my own localized and rebranded version of Eudora and many tiny modifications to games. Can you imagine a first party hacking tool like that today from the fruit company?