Netflix don't even hide their decision making process. It's more profitable for them to launch something new then to make more episodes of something older. (With certain exceptions like 'Lucifer'.)
Yes, because that's how capitalism works. Television is a business, not a charity. Why should a business "hide" the fact that it makes decisions based on profit? That's just how businesses operate. As Kai said, every commercial or subcription-funded broadcaster works that way. It always has.
Sure, used to be that shows build an audience, but truth is, for most shows, the longer they run, the more viewers abandon it, and the serialized format of today's shows keeps new viewers away.
The shows that succeed at building a profitable audience have always been the exception, as I said. Especially where SF/fantasy shows are concerned, because of the greater expense and the niche audience. When I was a kid in the '70s and '80s, it was rare for any genre show to last a full season, let alone more than 2-3. Serialization has nothing to do with it, because hardly any of those shows had any serial elements.