Either or? Yeah right! Those who are frugal with money - both their own & a client's, and those who are prudent with time - both their own & a client's, are smart enough to not reinvent the wheel each and every time something needs to be done.

If you have some type of ego problem with not looking in the repo for something that will save both time and money, then you won't survive and thrive at full capacity for too long!

Can things be done from scratch? Absolutely! I'd say about 80% of the time though, you can code and build from something that already exists and save time while gaining more money.

"Which term more aptly describes you, a WordPress implementer or developer?" There's a slightly large gaping hole in the pie chart you're leaving out by trying to put everyone in one camp or the other.
"Over 60 million people have chosen WordPress ". If you're the lone ranger type, then fine. I'll stick with the community. 60 million brains are better than "one or the other" any and every day.