And yet 99% of code written in Java, Ruby, <Generic OOP language here> is based on mutable objects. Its not about what is possible, we're all familiar with the

And yet 99% of code written in Java, Ruby, <Generic OOP language here> is based on mutable objects. Its not about what is possible, we're all familiar with the turing completeness of everything. It's about what is: the default + easy + encouraged in the ecosystem.