A lot of application already running in ethereum. Ethereum network is getting heavy.
That is true but they are also working to scale the network and improve it. So I wouldnt worry about it.
Problem is how fast are they gonna roll out the fork to improve the network? people might jump to a different blockchain if something is not done.
Actually, if ethereum network can't cover the activity on it, tokens easily switch to another chain.
Just a token swap with new chain and it is ready to go. So the problem only ethereum's own.