Is there an idiom behind this quote?

"Today 2 year olds can unlock an iphone, open, and close all their favorite apps all by themselves. When I was at that age, I was eating dirt"

I feel like there's a deeper meaning/understanding behind this. Can someone sum this up shortly for me?

Yes, there's a very deep meaning behind this. It's a metaphorical critique of the Kantian categorical imperative as expressed in the poetry of Keats. But you have to be able to spot the allusions to both Keats's sonnets and Kant's 'Prolegomena to any Future Metaphysics,' or else it just sounds like a comedian's joke about childhood.

In the areas of technology, 2 year olds today are as advanced as yesterday's 12 year olds.

technologically, today's 2 year olds are yesterday's 12 year olds.

the above are not idioms, but is a short summation.

"When I was at that age, I was eating dirt", is the idiom.he's saying when he was 2 years old he was pretty much a buffoon compared to today's 2 year olds.