Rafale Spectra is an excellent system but it is more of a self protection jammer and has very limited capability to provide jamming for other strike elements.
Our SPECTRA, the IAF version, will be able to jam across the entire relevant spectrum. Which is why we are getting low and mid band jamming with our version through ISE.
Also, the Growler and Rafale capabilities are complementary. While Growler provides standoff jamming, Rafale provides escort, standin and penetrating jamming. However due to the more advanced capabilities of SPECTRA, the air force would prefer the enemy is not alerted through standoff jamming, hence the Growler will become a liability rather than a force multiplier when it's actually used together with the Rafale.
Rafale doesn't need to provide jamming to other strike elements, it can do the job by itself. Only 2 or 4 Rafale are needed to do the job of 8-12 older gen aircraft when it comes to SEAD/DEAD. 2 Rafale can provide top cover and intelligence, 2 Rafale can move in, destroy a SAM site and move out, the top cover aircraft can perform BDA after, all this without alerting the enemy of their presence which the Growler will definitely succeed in doing long before the mission has even begun.
This is what Gen Mike Hostage said about the Growler:
“But in the first moments of a conflict I’m not sending Growlers or F-16s or F-15Es anywhere close to that environment, so now I’m going to have to put my fifth gen in there and that’s where that radar cross-section and the exchange of the kill chain is so critical. You’re not going to get a Growler close up to help in the first hours and days of the conflict, so I’m going to be relying on that stealth to open the door,” Hostage says.
If the USAF's Air Combat Command doesn't believe Growler is a first day of war aircraft, then it's going to be a waste of time and money to acquire what is obviously an outdated concept.
Lastly, there's the issue of downgrades. Whatever we get will definitely not be the gold standard.