$ wc -l lib/pry/*.rb | tail -1 -> 2801 total

I guess you're referring to lines of code. But if we're talking about that then you're actually pretty close to the original irb in size.

"It's also easy to extend, so moving commands out of core and abstracting them into their own external libraries would be simple"

Moving code around is simple yet pry's current extendability and abstraction is all of one plugin