Comprehension is what saves readers time. Write as much as it's needed for your readers to understand.

If I opened a page and fell on author's last one-liner, I'd be inclined to dispute the statement. It's void of context and arguments and we can surely find countless examples to contradict the notion.

Fewer doesn't mean simpler. Maths or programming expressions can be terse, yet so packed full of information that they take hours to decipher. We can find the equivalent in literature.

Sometimes to get your point across fast you have to use longer, yet more accessible sentences. To save readers' time, just write simpler, not shorter.