There have been a few experiments with the meta over the years (originally the current meta didn't exist and it wasn't till EU crushed NA with it at the end of S1 that it became popular). However, for the most part they just aren't successful. Double jungle was a thing for a while, and like you mentioned you could run a second duo lane top.
The problem is that gets beat pretty consistently by the current meta when they see it coming and know what it is. Double jungle worked for a little while with a farm jungle and a more support cc/invade jungle, where the goal was to run 3 solo lanes, farm fast in the jungle, and invade the enemy jungle (if lane roams and yours does too then it's 3v2) duo gank bot which would be pushed usually since it was 2v1. This worked for a bit, but pretty quick you learn to ward for the invades, and freeze bot lane. If they invade top side, you go steal their bot side jungle where your support can help out if they contest. Their bot lane gets starved bc when you freeze you can't gank the pushed lane, and the harass 2v1 is too much for the solo bot to keep up usually , so the current meta would succeed and out scale the double jungle.
Current meta has a strong item scaling champ paired w/ a utility champ who can survive w/ low gold (although riot helped them out bc they used to be so much poorer and riot felt bad) and so they are able to scale well into late game while only depriving one other champion who has to give up strength to help them out.
Then mid you have a safe short lane, which gets exp faster than others due to minion waves hitting a little sooner and being a little safer so it's easier to stay in lane for exp. You could put something else there, but then you either have a champ that scales well w/ levels in a lane that is harder for them, or don't get to use a champ like that.
Top lane is pretty similar to mid in terms of what you get out of it but is generally tankier or more sustained bc it's a longer lane and more dangerous. You can put other stuff up there but if you ran the same champs as you did mid you'd probably be at a disadvantage bc enemies could camp you to shut you down if you couldn't escape or they could burst you down.
Double bruiser bot was a thing, and you can still do it, bu it puts pressure on team to win early or just be better than the enemies, bc mages get stronger w/ levels more than ADC so if you put ADC in another lane the mage can burst them and do more damage w/ levels and less items, while the ADC vs Bruisers just has to stay safe and get farm. If the Bruisers don't get kills fast enough and shut down the bot lane, then current meta will out scale easily. There's other examples, but that sort of covers it for the most part.
Some stuff makes it through bc it keeps up (ie smite top solo where you actually keep up (or usually out level) the enemy jungle, or lane swaps w/ double jungle early), but generally the meta is the meta bc it is strong, and it pushes out other stuff bc it wins.