I'm all for shorter seasons - and I probably would've watched all the Marvel series if they were shorter - but I don't know if I buy the idea that the long seasons were entirely on Marvel / Disney instead of Netflix.
Orange Is the New Black completely owned by Netflix from what I understand, but that series is also 13 episodes/season and suffers as a result. And not only is each season 13 episodes, each episode is around 60 minutes instead of ~40-45 minutes like network shows. There ends up being tons of bloat as a result.
Fairly sure OitNB is Lionsgate.