Questions for those who want to keep the block size limit:
Does keeping the block size lead to less adoption?
Does less adoption lead to a less popular network?
Does a less popular network undermine the value of each bitcoin?
Bitcoins can be adopted without direct use of the blockchain. The blockchain ultimately keeps all the players above it honest. Off chain solutions allow for transaction scalability while promoting the use of bitcoins with ultimate settlement on the chain.
A secure blockchain secures the network and gives it value. A great payment network without a secure blockchain exists and is called the US dollar. We don't need to recreate that.
Any changes that potentially lead to that value being threatened (eg. failure to keep up with alternative methods) will lead to the failure of Bitcoin. Securing the network can be solved with various methods, hard transaction limit however cannot.
There is only one way to secure the network and that is through decentralized hashing power. Threaten that and you threaten everything that can be built upon it. Bitcoin has no significant alternatives or competitors when it comes to this metric.