I think there were a lot of historical contingencies involved. The nature of the language itself (small vs large alphabet, etc) is probably one of the least important.

There was an interesting BBC article a while back about the decline of German usage in science: https://www.bbc.co.uk/news/magazine-29543708 They put it down to anti-German sentiment during WWI (not WWII as I would have assumed!)

It’s pretty easy to imagine an alternative world where German was the common international language of science and became the basis of most programming languages too.

The importance of German as a scientific language was even greater before WWI than claimed in that BBC article.

While the BBC article estimates that of the scientific literature of the 19th century and of the pre-WWI 20th century a third was published in French, a third in English and a third in German, I believe that an estimate much closer to reality would be a quarter in French, a quarter in English and a half in German.