Why a size difference between similar scopes?

Greetings Everyone and Merry Christmas & Happy New Year's. My wife recently bought me a Crosman Optimus .22 air rifle which came bundled with a Cross Point 4x32. As I was initially going to purchase a crossbow, I bought a Cross Point 4x32, BUT, the size difference is very apparent. The air rifle scope is a good 30% longer, even though the crossbow scope has an additional parallax adjustment screw?
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As you can see above, the crossbow is on the left and the air rifle scope on the right. I am wondering why such a big difference in size for seemingly the same scope? I own both of these and I would like to know how a scope with the same magnification but LESS features is longer the the other? Thanks for reading.
 
A simple way of looking at it might be.

The lenses pretty much dictate the size of the scope for the most part. So, the scope is built around the lens. When a scope is designed the size it will need to be is taken into consideration as is the price point that they are trying to achieve when they choose the lens. Different lenses cost more or less and focus at different distances hence the difference in the prices and length of scopes.

There is so much more involved but you get the just of it.

So, in the end the scopes you are talking about were designed the way they are for specific reasons of which there are many. Use, length, weight, clarity, magnification, durability and the list goes on.