Of the list of priorities that Purism has on its plate, I would place Vulkan support as a low priority. It would divert Purism’s scarce resources from more important projects in my opinion, if Purism decided to invest in the development of a Vulkan driver for Vivante GPUs.
First of all, Collabora only made the initial announcement that it would start developing the PanVK driver to provide Vulkan support to Mali GPUs on March 25, 2021 and there have been no commits to the driver since May 6. Maybe development moved to a different location or maybe Collabora has decided to put the project on hold. Given the pace of Mesa development in general, I would guesstimate that 2-3 years is more realistic than 1 year before we will see working Vulkan support for any mobile processors in Linux.
Unlike the Mali and Adreno mobile GPUs which are widely used, Vivante’s GPUs are not used in many devices, and it is going to be much harder to convince companies and volunteers to work on an Etnaviv Vulkan driver. Collabora has 103 employees (almost all software developers) and it is a firm with a lot of experience in this kind of dev work, whereas Purism doesn’t have anyone on staff with this kind of experience, so it would have to hire additional developers with experience to work on adding Vulkan to Etnaviv.
Currently Purism is paying 11 software devs to work on the Librem 5 (according to its Team page) and it appears to me that Purism has financial problems which is why it changed its refund policy, had to cut back on the number of L5 developers (which were 15 at the beginning of 2020), and decided to only develop one new laptop model instead of two. In other words, you are saying that Purism should stop paying a couple of its current developers, so it can hire some others to work on a Vulkan driver that probably won’t be ready for a couple years.
Which developers do you propose that Purism stop paying and which projects should be dropped or delayed in order to pay for Vulkan drivers for Vivante GPUs? Squeakboard? Megapixels/V4L2? Fractal? libhandy/libadwaita? phoc/phosh? smartcard driver and OpenPGP integration with apps? Adapting GNOME apps to use libadwaita? work on suspend?
In my opinion, Purism’s highest priority should be to get get a working Linux phone, and diverting funds to pay for Vulkan development is only going to delay the Librem 5 even more. Maybe Purism can find volunteers to work on Volkan for Vivante GPUs, but I doubt it, and frankly developing Phosh and libadwaita is far more important for the future of mobile Linux than Vulkan support, and will benefit far more people as well.