Open source should not be a threat just like Linux isn't really a threat to Mac and Windows. It all depends on who will get the network effects first (if there even is network effects in LLMs). People pay for windows because of its strong network effects eg Microsoft Office and countless software that run on windows. Even though Linux is free most businesses today don't use it on the desktop.

Opensource also means do it yourself and most businesses don't have time or expertise to do that, but this very issue creates a market for 3rd party providers that use open models to compete against Anthropic. So hardware and compute availability becomes somewhat of a moat.

The business feels like like web hosting before cloud computing. Web hosting in itself does not really have a moat, but than again AWS appeared with their abstractions created lock-in and network effects and disrupted the hosting industry.