I occasionally google "PHL Chase lounge Reddit" as the chatter on this topic is more active there than it is here. I found this post from two months ago to be helpful:
TheTwoOneFive 2mo ago -
PHL as of July 4 looks like there is still a ton of work left to do - I wouldn't expect it until the end of 2024 but more likely 1H25 at the earliest https://imgur.com/rWHvpWK
I don't know why lounges in PHL take so long to build, but this one is no exception.