I have a feeling that recent block of 8 JF-17B we inducted, some of them may be JF-17E (Growlers)
@Windjammer spoke about last year.
https://defence.pk/pdf/threads/jf-17b-ew-growler.587580/
True, possibly because the technology didn't mature as fast. An upgrade makes sense when significantly better variants are available. Marginal improvements in technology do not justify the cost-to-benefit ratio.
But here is the good news, after developing JF-17 Block-III, west will open up to share its upgrade or they know through China, Pakistan will get those technologies anyway and their chance of doing the business will be lost. Improving economy will also make every supplier soften up and create in-roads before the others.