This is an aged discussion about the scalability of Bitcoin. For me it is possible as we already have a lot of new cryptocurrencies that are extremely fast transactions and cheap transaction fees. But most of the common issues from them is decentralization, which Bitcoin has. Some projects discussion and challenge are the decentralization, you manage to solve the scalability but the decentralization?
The talks about the security across blockchain is only undisputed when it comes to Bitcoin, other blockchains are being perceived not to be totally possessing' the features of a blockchain. As much as alternative chains present themselves to solve the challenges associated with scalability, concerns have been expressed over the true nature of their acclaimed decentralization. I totally agree with the point said about other blockchains not being truly decentralized.