$500K is lots for a 30ft standard luxury cruiser, $500K for a special build Ferrari is normal.
No doubt the 300 is a step above a standard luxury cruiser, glass roof as an example. Is it above a Cruisers Inc. or SeaRay or other high-end brands? My guess is the old CEO thought there was a market and distracted the company in this direction. They are expensive because they are not mass produced and it probably takes them 3-5 times the resources to build one.
I'd prefer MC stick to building wake/ski/surf boats and not have one offs that demand a disproportionate amount of the same engineering resources that the bulk of customers need support and innovation from.
In other words, as cool as the 300 is ... it is a gorgeous boat ... ultimately it is a distraction. I'd rather have more innovation and advancement in wake surfing / boarding than a nice boat to look at.