I guess everyone has left the building, leaving a reply in case you see it.
>I disagree with you premise that R is not popular among machine learners
I know what you are saying, and I agree, that is why I chose my words carefully.
I am not so sure about the *scope* of the 'bleeding edge' part
The word I wanted to highlight is "scope". The population that identifies themselves with any of these labels: machine learners, statistician, data scientist, data modeler, actuarial scientist, prediction consultant and all other variations...is huge. So whether R is popular or not depends on whom you want to include and whom you want to exclude.
There is a quite a lot of variation here. In one subset, if you know the ins and outs of R you will be taken for a wizard, in another subset just listing R/MATLAB as one of your major skill will actually work against you.
> what's wrong with "pushbutton" libraries?
Nothing at all and I did not claim its wrong either. In fact I said that is one of R's strengths. For people who arent into the theory of statistics or ML then R can be a heaven sent. Especially if all they want to do is try out a catalog of algorithms.
The analogy I use is that of an automobile industry. If your goal is to be a run off the mill automobile driver/chauffeur R is your competitive advantage. If your goal is to be an automotive engineer (design new models and algorithms) R is an inferior tool. In fact if you want to be a F1 racer, you have to look elsewhere too. Like every tool it has its sweet spot, as long you don't venture outside its golden.
R is bad building material, but if you dont want to build something novel in the first place (in a statistical or machine learning sense), just call a canned solution on your (medium sized data) data, then R is the boss. If you try to do anything meaty or clever then you have to be careful with R's gotchas. It helps commoditize data analysis and popularize techniques amongst its large base. If you want statisticians to be aware of some cool technique, you have to release an R package, because if it isnt in CRAN it does not exist.