Do you often read dropped novels knowing they won't be finished, and if so why?

Can't say for sure. I tend to avoid novels that stopped the translations or was droped by the author. Until now never happened to read one that would have no end, but probably if the story is interesing and well made I would give it a try.
And there is novels with a end that simple continue to do the same thing over and over, a new young master of powerful clan waiting to try to mess with mc just to get his clan killed. and that over and over. those I drop. Against the Gods had that. I liked it very much but mc was always after trouble, he said it would make him stronger faster but still a repeat of everything. 

I've done it a few times when I was on a mini fanfic reading spree. All of them dropped yet I read em anyways. 

Not yet, but i probably will if it's quick wear. It's episodic. I can pretend it's ended at any arc... Well, as long as it's more than 3 arcs... 

Sometimes I read dropped novel to search for idea to make my own novel since some of those dropped novel have a good story until something goes wrong. 

Hah it's banned for good, good! it's also for your own good. That novel starts awesome but degenerates into utter trash.
Rarely I read super good fanfics, as long as they have most of the story written. 

Yes , because most of the novels here have very good first half and terrible second half, I assume from the start that I'm going to drop it due to poor writing half way trough.
Just about when the author starts writing for the word count, as opposed to for the adventure and fun.

It is rare for the novels to keep my attention till the very end. 

I tend to stay away from ongoing stories, unless they're really popular or the subject matter interests me. 

I don't start reading anything till 10-20 chapters in because so many get dropped 2 or 3 chapters in. 

I actually prefer reading stories without an end. I always feel a deep pain whenever a series actually concludes instead of just leaving me in that wierd limbo of the novel being "active". 

While the number of completely translated novels continues to grow, they will always be a tiny fraction of the novels being translated here. It’s basically impossible to limit yourself to those.

In addition, many of the novels being translated are still ongoing in their country of origin. The fraction for these being completed is significantly larger, but still only a fraction.

Neither the translator nor the author is guaranteed to finish their work. Ever. So you have two points of failure for the significant majority of these novels: the translator, and the author. Either one of them could stop at any time, for any reason, and the novel - as far as you’re concerned - ends there.

Better just get used to reading stories without endings. 

Maybe... if the novel is interesting 

usually not. i've read a few that ended up gettin dropped early/mid binge, but going into it, i probably won't bother if i i know it'll never continue.