Why do cyclists use thin bottles?
Inertia.  Bottles are about that big because that's how big bottle cages are, because that's how big bottles are.... repeat.
Another cause is that a 10cm bottle would be larger and harder to hold/easier to drop while riding.  Most riders would drink while rolling on the bike, so its potentially bumpy, with a layer of sweat/sunscreen/rain making things a bit slippery too will add to drops.
Lastly - added width will poke out into the airstream more, contributing to a drop in aero efficiency.  There are some expensive bottles that are deeper vs their width but they cost a lot (hundred dollars a bottle ?!)  and their overall capacity is probably no-more than a regular bottle/bidon.

The width also limits the chance of clipping one's bottle with your feet while pedalling hard.

Later: you reminded me of the Growler Cage - its designed to hold a 64oz jug (about 1.8 litres) and the vessel is between 4&quot; and 5&quot; wide (100-125mm) depending on material.  You'd want to avoid a glass/ceramic one, and would choose stainless steel or plastic.
Also be leery if you're transporting anything across boarders/state lines or into a jurisdiction with different alcohol laws - even when filled with water, these look like they might hold booze and could attract legal and/or criminal attention.

Downsides of this is that its enormous, adding significant mass to your bike and only held on by two bottle cage screws.  Those might be enough for a single bottle, but this is ~twice the weight and has more leverage on those same bolts.
Also, as reported these are likely to hit your feet, pedals, or cranks on every rotation.  That gets annoying really fast.  I'd expect to tap it with my calf muscles or trousers too.