So I will give a few simple basic concepts before you read the article from SearchEngineLand.
The fundamental idea of a business is to maximize profits.
There is a saying I like and the author of this PPC article uses it:
"Revenue is vanity, and profit is sanity."
So your PPC bids can be very high and you will generate more revenue, however you will lose money.
I see this all the time with clients and even for my own products. E.g. if you have a low cost product you can spend a lot on advertising, then you will need to raise the price to cover these additional advertising expenses. I prefer to call them advertising investments in growing your business.
Also do not take PPC advice from Google Adwords employees. Think about it, their goal is to maximize Google's profits not yours.
People waste a lot of Google Adwords money by being #1 when it is better to be #3 as close to as possible to the natural/organic #1 ranking. Humans focus their vision on the #1 natural ranking spot and 85% of them skip the paid advertisements.