The comparison is natural because Python is a general purpose language which happens to be used for data science, the same can be said about Julia. The others languages mentioned are not really that great for general purpose programming.

But I agree with you that in the short term it is a replacement for Fortran, Matlab and R. But a new language has to start somewhere. Attacking the niche filled by these language is natural as these are old, dated and ripe for disruption. The key is to gain some critical momentum and user base. That will carry the language to other domains.