To those of you understandably worried about the future of bitcoin, consider this.
1. ETH is not a direct competitor to BTC, at least not in all aspects. It is not a currency, and it is not sound money. Think of ETH is a platform for smart contracts which facilitates the digitization of aspects of the fiat economy. As such, it attracts investors that are not interested in bitcoin. The types of investors who talk about 'Blockchain' but avoid pronouncing 'Bitcoin'.
2. Now bitcoin is also meant to be a platform for smart contracts, and as such ETH will eat some of its lunch. But right now the smart contract aspect of bitcoin is not the main focus. We are interested in bitcoin as sound money, as a medium of payment and as a store of value. Let's get that working first. It is huge, almost unimaginably so.
3. The blocksize limit will go up. Market pressure is just too strong. This is a temporary pain point, but not the main worry.
4. The main worry is that having a single implementation of the protocol is a point of failure, and an existential threat. Because, as we see, a private company can attempt to co-opt the protocol in order to further their own business plan. I am heartened to hear reasonable people like J. Garzik and B. Armstrong make pronouncements in this direction.
5. An example of co-optation is to take advantage of the pressure to grow the block limit in order to inject segregated witness into the protocol everyone runs. This technology was first developed by Blockstream for the propietary software they market to private clients. It would give an interoperability advantage for their products to have that code present in the common protocol. Also, it is a step forward in the implementation of the Lightning Network, which is a system their investors want to implement, because it provides a way to get returns on large BTC holdings, by operating hubs. As many here have pointed out, this comes at the expense of transaction fees, which are miners' long term revenue source. This should be resisted, as miners are the custodians of the network. If the blockchain is not secure, BTC is not money.
6. There should not be invitation only consensus roundtables or conferences arranged by interested parties to plan or decide the future of bitcoin. There should ideally be a spec, multiple implementations, and market forces at play.