I've experienced this in my own work as well. The extra verbosity of Pandas data frames compared to R data frames doesn't bother me anymore. Sometimes I miss the Lispy homoiconic magic, but not enough to make me want to use R at work.

I still use it once in a while for heavily "statistical" stuff that doesn't ever need to be "productionized", but for run-of-the-mill machine learning I see no reason to use it over Pandas.