I feel for the author, but Google is not "forcing Routebuilder to shut down." Google is instead telling the owner of Routebuilder to find another API to use. Routebuilder can find another API, pay to license data, etc. There are alternatives rather than "shut[ing] down."
I know this probably sucks for the author, but this is the risk you take when building your product on top of someone else's API without a separate contract in hand--as many Twitter developers found out firsthand a few years ago. Their service, their rules.