There was the Triomphant in between which served as a platform for various intervening technologies, including pumpjet propulsor & the K15 reactor. The only real 'new' addition on the Suffren was the NEP.
Not saying the Chinese next-gen boats won't be quieter than their current ones, but that we can't assume they will be any better than Russian subs of the last generation (Improved Akula).
Either way, IUSS networks are here to stay. Russian subs even today are way quieter (Yasen) and you don't see the US abandoning SOSUS in the GIUK gap or elsewhere. There's not many better ways of monitoring large swathes of territory for signatures...it gets even better in regions where you know the enemy will be forced to navigate through relatively small specific channels (like Malacca, Sunda, Singapore straits).
Bottom line is, IUSS/SOSUS is not going anywhere anytime soon.
From what I understand, there is incorporation of latest generation advances in magnetic anomaly detectors among other sensor technology to provide augmenting to traditional hydrophone tech in SOSUS et al. These (along with proper surveying and calibration techniques) take advantage of increased computing power available today to contrast both relative sources and holes of sound by cross-arraying all of this w.r.t the background noises and resonances involved.
SOSUS is just a holdover legacy name when it has changed considerably and is staying ahead of the curve of sub quietening....with exercises and robustly testing involving one's own quietest/smallest submarines to know the systems capability.
More broadly speaking the arc from Japan to Vietnam (with now philippines under Marcos jr. crucially making large overtures to the US again on bases in Luzon, in contrast to Duterte before) is where India needs to focus on helping weaponize where possible.
A grey "neither confirm nor deny, FAFO" WMD deterrent will also be part of this strategy. Very promising that the South Koreans have adopted SLBM already and that the Japanese have a good plutonium stockpile and have bomb tech they can quickly assemble at the ready (all hushed up for time being)....along with active increasing interest in how this relates w.r.t Taiwan as well in concert with the US. We will see if there is a role for India here too with time.
Brahmos (PH and Viet) in the southern arc is appearing as just one small part of this as well.
CCP has really picked the wrong enemies at the wrong time for itself given its demographic crisis and other ones mounting. We will need to be coordinated with others to exploit all of this. India made small part of its intention known when the AUKUS TOT vote (PRC was accusing the whole thing as some kind of nuclear proliferation) came up in IAEA and India voted to deny it be brought to tabling any kind of motion....rather than take its traditional neutral stance that China had grown accustomed to.
It is in India's interest now to see the whole eastern + southern seaboard of Asia Pacific weaponize fully to maximum amount possible and be on friendliest terms with them all....so we can all ride out the long term unfolding internal grave issues within PRC that will enforce reality there long term given the complete lack of trust + even Malthusian level fear the totalitarian psyche CCP had and has with its larger people that precipitated all of it.
trishul-trident.blogspot.com
rbt-defense.blogspot.com
www.hindustantimes.com
www.navalnews.com
