Boeing did have a competing design, the Boeing 2707, however is was cancelled for the same market and economic reasons that Concorde struggled with.

https://en.wikipedia.org/wiki/Boeing_2707

Boeing knows how to make sonic booms that don't shatter windows?

I believe the idea of the parent comment is that Boeing knows how to get the government to let them shatter windows

We tried.

https://en.wikipedia.org/wiki/Oklahoma_City_sonic_boom_tests

The outcomes were SUBSTANTIALLY worse than the US government expected. The results of this study are why even war planes rarely go supersonic over the continental US.

I remember the sonic boom over the Seattle area in the summer of 2010 when Obama was in town. A seaplane accidentally violated the 10 mile exclusion zone around Air Force 1 at Boeing Field and two F-15s were scrambled from Portland International Airport (Oregon National Guard operates the fighters tasked with protection from Northern California to the Canadian border). It was quite exciting.