Regarding the lack of 6-place experimental aircraft, I'd imagine the market is still a bit small for that to really pan out for the most part. As a percentage, there aren't a ton of SE 6-place aircraft as it is, so you're trying to attack a market segment of A36 and PA32 owners/would-be owners to switch to the homebuilt route. Very few are being purchased new, so you're trying to compete against $150-$300K used Bos and Lance/Saratoga/Six at this point, which is pretty much a wash by the time you bought a kit and built it, then bought an engine/panel in it. Sure, you have the side benefits of owner built-maintained, but from a dollars and cents perspective it's mostly a wash. Unless you want to design a twin-engine 6-place experimental, but then the market it still pretty small as many don't want ME birds anymore and you're back trying to compete against 310s and Seminoles which can be had likely for less than what you can build it for as an experimental.
The 2/4-seat homebuilt aircraft have a lot more advantage both in cost and competition.
That said, a Velocity Twin 6-place would be an amazing bird to own, if you had enough runway to make it happen.