critique:  Bitcoin is one of many thousands of crypto assets, and anyone can create more whenever they want. Bitcoin therefore is not scarce and can't be valuable.

rebuttal:  Crypto currencies are not scarce, but bitcoins on the bitcoin network are. Anyone can indeed clone the open-source bitcoin codebase at any time, and launch their own coin, but they can't clone the acceptance, name recognition, and security that only the bitcoin network enjoys. People have been cloning bitcoin since 2011, yet no clone has come close to matching bitcoin's marketcap and network effect.

As an internet protocol for money and a store-of-value, bitcoin enjoys extremely strong network effects. The lock-in created by thousands of businesses, and millions of users & investors, who have a vested interest in bitcoin specifically is extremely difficult to overcome. This is akin to what we've seen with base-level internet protocols over the past 50 years. Foundational technologies like tcp/ip and smtp have dominated for decades, despite their technical flaws and emergence of countless competitors. They are simply too ingrained in the internet ecosystem to unseat, and developers and businesses choose to build on top of them instead. Bitcoin is proving similar.

Along these lines, CEO of Micro Strategy, Michael Saylor, recently observed that once a tech company or platform with a network effect achieves a $100B marketcap, and does not have competitors similarly valued, the platform is likely to be a dominant runaway success due its network effects and a winner-take-most dynamic. Bitcoin surpassed $100B in marketcap for the first time in 2017 and has remained dominant as a pure digital money and store-of-value throughout its entire history.