I believe the current limit is about 7 transactions per second, which gives us 604800 transactions per day, way above the current ~100000 transactions per day on the network.
Nah this has already been said a million times that this is the max transactions possible if all transactions are the smallest transaction size (a coinbase transaction).
In reality all the transactions are bigger than this allowing more like a max of 3 or 4 t/s
If so, an upgrade/fork is vital, things tend to grow quickly on the Internet, we might not have much time to scale the network before problems start to arise.
Well, real money is on the line and there's an avalanche of bad press and misconception to contend with.
A stupid app can explode from nowhere, but BTC is a hard and complex sell in comparison. I think adoption will come top down and it'll be slow until a lot of extra things are in place.