I honestly don't think Imagination is trying to become a "big player" in the first place though.
To me this just looks like Imagination Tech trying to stand out from the crowd in the mobile graphics market. With Intel dropping out of the mobile market, that leaves just Apple and Mediatek as notable Imagination customers. Apple taking their GPU internal in the future is probably not a completely implausible scenario, so Imagination Tech will want to have some way of at least appearing to offer something unique, to avoid becoming completely irrelevant in this market (I doubt they will be able to maintain the revenue required to develop competitive GPU designs with just Mediatek as a customer).
With that being said though I do think that hardware accelerated ray tracing will become the standard at some point, but it will most likely be driven by AMD and Nvidia.
Edit: Actually, now that I think about it, this could be a play to get out of the mobile market, but not to get into the gaming market (at least not primarily so), but rather to get into the professional graphics market. This market would be willing to pay a couple of thousand dollars for a ray tracing co-processor in a volume that could possibly make sense for a company the size of Imagination Tech. This would however mean that Imagination Tech would have to start selling hardware instead of just licensing designs.