Recursive descent seems to be the go-to parsing technique for compilers both big and small now. I like how all the repetitive functions for each level have been refactored into a "general_recursion" function, but if you want to make it even simpler and yet more extendable, table-driven precedence climbing would be ideal:
I think the fact that everyone just writes recursive descent parers tells us in practice that there isn't sufficient value in using more techniques like table-driven variants and they don't make anything practically simpler.
If it was significantly more clear, people would use it in practice! This makes me think it is not in fact significantly more clear.
I did research work in parsers, and I work professionally in compilers now, and guess what when I need a parser for in-fix expressions I just write a recursive descent one manually, it's never an issue.
In context of more complex language with small set of infix operators and their precedence classes it is probably not worthwhile unless you really want user-defined operators.