Blogs and other online writing platforms allow people to write as much or as little as they want.
However, it shouldn't be about what 'they' want but about what the reader wants.
A well-known blogger recently wrote a very long piece making good, but very few, points.
I'd like to know how long the average reader persevered. I read to the end and wished I hadn't.
I was tempted to add the dismissive tl;dr (too long; didn't read) comment. But, since I had read it, that wouldn't have been fair.
I realised that genie is out of the bottle and online writers feel they can do what they like, but now that most of us are online, it means that we have to fight for the right to be read.
And one way to earn that right is to respect the reader's time.