I think at some point you need to take the old ship out into the ocean and use it as target practice. Retrofitting a ship is done as long as the ship can compete with other navy ships. Once it costs more to upgrade the ship than to build a new one altogether it is time to retire it. I think Ether is still viable and has a lot of influence in the crypto world, but at some point when these new mainnets like EOS and TRX go live in another month we will see a shift toward the newer faster tech. If there are no major problems then we could see a faster migration. But I don't see a plan that allows Ether to scale the way eos or trx were DESIGNED to.