I can't disagree there. However Inworldz is set up a little differently. They don't rent small plots. They only rent full sims... and leave it to landholders to rent out plots. That way they don't wind up competing with their own customers like LL does. So no, I don't agree that Inworldz doesn't have a "healthy small plot market". I have an entire region I rent out... and I've publicly encouraged people who can't afford full sims to consider renting 1/4 or 1/16th plots. There are enough active users on Inworldz to do support the land economy... and by the end of 2013 should be a whole lot more.
Inworldz has between 150 and 300 concurrency at any time. No other grid outside of SL comes even close to that. Inworlds, with their 1000+ sims... has over 7,000 active users. Comparatively, OSgrid with what, 7 times more sims than Inworldz, has about half that number of active users. Inworldz has more active users than the next three top grids combined. Beyond that, other grids have far less. The stats indicate there are "grids" out there with as little as 2 active users. (I have to admit I wonder how that even warrants a listing. Does my Simonastick count as a "grid"?). :D
At this stage of things... we can expect no VR grid outside of SL to have any great concurrency or active user count. We're not at that place yet. In fact, Inworldz first true public advertising since they've been open is coming in March. We'll see what kind of public attention that brings. But Inworldz doesn't engage in small-plot renting. Their goal is to provide the best, most stable grid platform they can provide. Beyond that... the rest is up to their customers. They're not going to compete with customers like LL regularly does theirs.