This is...odd. They are clearly looking to start something 'new' in the industry, hence their choice of 1/8th scale rather than 1/9th.
Why do people NOT buy high end sixth scale action figures, even of licenses they love? Price and space. They cost $220, and take up a lot of room.
Mezco's One:12 Collective is an answer to both problems. They are still producing very high quality stuff, but at $70, and they take up a lot less room. And the response has been extremely good, proving it is possible to do something new in the market and build a following.
Mezco also wasn't trying to get current high end sixth scale collectors to step down in price and size. They were trying to get Marvel Legends, Star Wars Black, and other 1/12 collectors to step up. Companies like ThreeA, Mafex and Tamashii Nations had already greased the skids with prices in the $50 - $60 range.
Mezco also has another advantage when doing something similar - they aren't already tied tightly to a particular scale as a company. Remember when Hot Toys tried to do 6" figures? People think of Star Ace as a sixth scale company, and getting them out of that mindset might be tough.
I think their biggest hurdle is the price point. We know there's a market for $200 - $250 sixth scale figures. We know there's a market for $75 1/12 scale figures. Does that leave anyone for the market in the middle?