You're welcome. For the sake of argument let's assume your target customers are small teams. I'm going to try and pin you down on one area you keep assuming is true: "There's a wide variety of reasons people might want that." Can you name 3? I can't think of a single application a team might use that would require layer 2 connectivity. File sharing is done with dropbox, email and other server or saas solutions these days. Modern version control systems work across the internet. VoIP would be through a provider...
There are a lot of other areas you can apply this technology, but there are already tons of players in those spaces.
One user has a CAD app that must talk to its license server to work. With this, they can have a license server and their distributed team can use it. (Consulting company.)
There's a few users who just like the convenience of being able to do things like share screens, drop files to each others' machines, etc. as if they're all in the same room. There are other ways to do it, but they find this easy and straightforward and the services are already built into the OS.
A few users have security concerns that make them more comfortable with direct file transfer over their own encrypted LAN than with Dropbox, et al. These are medical and financial sector users.
But ultimately I think you are at least partly correct. Most things have moved into "the cloud," so a significant proportion of users have no pressing need for direct connectivity. This makes it likely to be a niche market.
Of course you can go further and ask "why has everything moved into the cloud?" There are multiple reasons, but one reason is certainly that direct connectivity is hard. But now you have a chicken or egg problem: nobody builds apps that require direct connectivity because it's hard, and there's little market for making direct connectivity easier because nobody builds apps for it. Those kinds of catch-22 scenarios are murderously hard to escape, either technically or marketing-wise.
One application that doesn't fit the mold though is private network backplanes for cloud servers that span data centers and cloud providers. I've got a couple users who have servers on multiple providers on multiple continents (Amazon, Digital Ocean, etc.) and this lets them have a single shared encrypted private backplane with a few minutes' setup time and no manual configuration.
I've considered following that line of thinking and building some kind of "meta-cloud" solution, also possibly integrating with Docker, OpenStack, etc. The idea would be "SDN over WAN and between providers." I've gotten a few positive comments on that concept, but I'm at the early stages of exploring it.
There are a lot of other areas you can apply this technology, but there are already tons of players in those spaces.