This is starting to look like a normal thing now. Joomlart is doing the same thing now, No new templates, lots of open support tickets but yet still having sales and selling the old templates. I was a long time Rockettheme user and ended up at Joomlart, then JoomDev (which shut down) and now JoomShaper.
I will be honest, I have figured out, the free stuff it the best to use and just customize to your needs. Joomla is starting to become an all-in-one tool, unless you need advanced stuff. And it's starting to look like the most reliable companies are Joomshaper & YooTheme.
I personally use Helix Ultimate now (free version) along with YooTheme's Zoo & Widgetkit. And I just customize everything to my needs using custom CSS and HTML. You can makle everything work for you. Joomla has become really advanced. J5 is looked down on by some devs, but I think it's the best yet and replaces the needs for most frameworks and extensions even as most stuff can be achived thru J Articles.
From the way things sound here, something seems to have happened that Rockettheme is not ready to talk about and are instead pushing the fact that Gantry is open source. And yes there are other Gantry providers if you look. Over at Joomlart is you visit their forums, you will see a thread called The Future of Joomlart? - And you will see the number of posts, their last template was released in July, 2024 and people aren't even getting support repsonses. There are so many threads in their forums that haven't been repsonsed too. They re-launched Gavick as GK Framework, whihc looked so promising as a leightweight template - it was so buggy and messed up, now they seem to have just abonadoned it and left it as is with the last update in Oct of last year whihc actually fixed nothing.
I can't sit here and defend RT, but I also understand they way the business is going. I've used Joomla since 1.5 and now use J5 version and I run a large site using Joomla. We went from using tons of extensions down to just 2 as I mentioned before. And a basic free tmeplate is all you really need. And I think that is where Joomla is heading, to more of an all in one tool with extensions just being add-ons for advanced users.
And I will be honest J4 & J5 did have alot of changes that alot of devs didn't want to take the time to re-write, only the larghe providers did proper upadtes. Joomla even launched their backwards plugin to try to allow J4 extensions to work with J5 because of this. But that is suppose to disappear with J6 next year, I have asked for it to stick around permanently and got the whole 'we will look into it'. K2 is the biggest example of a dev not willing to update their extension for the new J versions and literally blaming Joomla in his online rant.