Python and Ruby although in the same category have still different mindset. It is understandable the way you think fits Ruby more.
I tried to learn ruby and was put off by all the magic, last value calculated is magically returned, the useful but cryptic method calls.
It is shorter and more implicit, I like the explicit approach more.
to give you my perspective on the points you made:
- self: more explicit, I would prefer to write it, because there is classmethod(with cls) and staticmethod(without any) params.
- spaces vs. braces: I don't hate braces, but spaces makes it more readable, less things I see(whitespace vs. {}) the less distracted my eyes are from the the characters that do the actual work, you get used to it, I like it more to be honest.
- len(string) vs. string.length: again, no preference, I am used to both.
- py 2 vs py 3: it is not never ending, I helped move a 170K Django project from Django 1.6 to Django 2.1 and python 2.7.4 to 3.6 in a span of a year, we were mainly 3 people working on it on the side, our work was not even in the sprints, 2 senior engineers + 1 really good QA & deployment engineer, it took 1 year because the platform was business critical and we incrementally fixed stuff. At this moment whoever still runs py2 either has been lazy, does not care about technical debt or their business does not value solving technical debt, so they can not allocate time to do it. This is my opinion, might be wrong, maybe there are other reasons also. But the change had to be done for the health and longterm viability of the language.