Switching bot and top is actually an extremely common strat in mid/high elo. The botlane that is ahead and has taken the tower moves to the toplane to take the tower there and control the herald, while the toplaner moves bot to either freeze farm or splitpush.
However as said by others you need to control the dragon pre 10 mins while there is no objective top so you always put 2 people botlane at the beginning of the game. Only when herald spawns at 10 minutes does it become a good move to put 2 people top.
If you switch your bot lane with your top lane, enemy team would have dragon pressure as they have 4 people on the bottom half of the map and your team would have 3. Some bot lanes do end up switching eventually after taking bot tower and dragon to contest herald and top tower.
It's more gankable because there are 4 sides to gank from, and bot laners are generally more prone to ganks than mid laners are, so its easier to go bot lane than it is mid lane.
Now the reason top laners don't go mid is because of the short lane. You can't take extended trades in the mid lane because the enemy is always a few steps away from tower, so that leaves out a lot of top laners.
They also tend to lack wave clear, until they buy items like Tiamat. Mid laners need some form of wave clear, its why Taliyah isn't really viable mid anymore.
Most top laners also don't have ways to deal with poke, especially if they're melee. It's why ranged match ups are hard to deal with in the top lane, but at least there the ranged champs aren't 2 feet away from their tower to hide if they get jumped on.
There's even more reasons why mid laners go mid but the response is already getting long enough as it is.
Another reason would be because ADC champs are a sitting duck when left alone.
I saw ImaQtpie say this on one of his streams once.
There are a few exeptions but in general if a bruiser/tank played smart top and farmed in the back not feeding the adc player they are facing then they should be able to beat the adc player when they hit six.
Ive been up against adc champs top alot as Sion and Poppy and I was able to crush most of them if I played it decently enough.
Sion was especially easy, hit the ADC with your R,E,Q,W combo and their gone, Poppy is a little harder but pin them against a wall and their basicly dead already.
And on top of that they cant ever push the lane or they die against the 2v1 (jungler).
In all honesty though, Ive been wondering the same thing and the only actual way you'll find out is by trying it out.
However as said by others you need to control the dragon pre 10 mins while there is no objective top so you always put 2 people botlane at the beginning of the game. Only when herald spawns at 10 minutes does it become a good move to put 2 people top.
I guess mid is also not viable because its shorter and is more gankable?
Now the reason top laners don't go mid is because of the short lane. You can't take extended trades in the mid lane because the enemy is always a few steps away from tower, so that leaves out a lot of top laners.
They also tend to lack wave clear, until they buy items like Tiamat. Mid laners need some form of wave clear, its why Taliyah isn't really viable mid anymore.
Most top laners also don't have ways to deal with poke, especially if they're melee. It's why ranged match ups are hard to deal with in the top lane, but at least there the ranged champs aren't 2 feet away from their tower to hide if they get jumped on.
There's even more reasons why mid laners go mid but the response is already getting long enough as it is.
I saw ImaQtpie say this on one of his streams once.
There are a few exeptions but in general if a bruiser/tank played smart top and farmed in the back not feeding the adc player they are facing then they should be able to beat the adc player when they hit six.
Ive been up against adc champs top alot as Sion and Poppy and I was able to crush most of them if I played it decently enough.
Sion was especially easy, hit the ADC with your R,E,Q,W combo and their gone, Poppy is a little harder but pin them against a wall and their basicly dead already.
And on top of that they cant ever push the lane or they die against the 2v1 (jungler).
In all honesty though, Ive been wondering the same thing and the only actual way you'll find out is by trying it out.