I know I’m a little late to the party, but I can’t resist a topic about business models and pricing! ;p
If you don’t mind, I’d love to just give you my 2 cents:
* 39,95 for unlimited sites is really underpriced for the value you get. (Even with yearly renewals).
A lot of people will be using GP to earn money and build sites for clients, which is great, but the current pricing doesn’t take that into account.
I would encourage you to bring back some sort of agency type license and distinguish personal from professional licenses.
Even at something like $99 it would be an insanely good deal, considering most will be charging their clients (probably many) multiples of that. Adding something like a “white labeling” addon exclusively for this license would make it all the more valuable and great positioning against your other option.
* Recurring billing
Another thing I would consider is automatic/recurring renewals. As long as you are upfront about it and make it easy for people to cancel (and just remind them of a renewal coming up) – this is both convenient (for customers) and predictable/consistent (for you) (which also makes it a lot easier to hire additional help if you need it, since you pretty much know what to expect). Add in automatic renewal discount and you’re golden.
Moreover, adding a “renewal window” were you give manual renewals a  day period to renew their license with the renewal/loyalty discount, or let it lapse and later renew at the full current price, would be a good option.
This stimulates loyalty and ensures it gets rewarded. Lot’s of membership sites, WooCommerce and EDD also use a similar model. It’s win-win and has nothing in common with the d-bag marketers sneaky approach.
* Slowly increase the price (for new members only)
As you keep improving the theme and addons, the more valuable it becomes and this warrants a price increase. Even if this means a little less total sales, it also means higher margins and less support.
$39 x 1000 = $39.000
$49 x 800 = $39.200 (20% less sales = 20% less support = less hours for roughly the same bottom line)
You deserve to be compensated for your hard work. And you need a healthy profit to be able to sustain it long term.
Something else that comes to mind:
The more themes you create, the harder it will be to update and support all of them. You see this a lot with certain theme clubs were most themes don’t get updated much after the initial few months.
You also see this a lot with Android OEM’s – they keep spitting out new phones, essentially leaving the previous ones without anything but security patches.
Short term this makes a lot of sense, since new stuff brings in more business, but it also results in a lot of pissed of people.
This makes it hard to create loyal customers and makes your business model more transactional than relational – meaning you have to constantly replenish and make up for leaving customers. This kills a lot of businesses long term.
Especially if it’s just you and/or a small team, the leaner the better most of the time.
Anyway, I’ll stop rambling now.
GP is a truly excellent theme and we all benefit if you have the means and proper compensation to keep it that way!
Thanks & keep rocking 🙂