The navy still has the Bears for long range operations, but only with limited strike capabilities. The P8Is on the other hand will add new strike capability, the main problems still seems to be the US weapons that are cleared to us so far. With SLAM-ER, JASOW, or SDB the P8Is would be great bombers too.
However, main question remains what targets are there for IN? The only enemy with a carrier is China, which is neither in operation yet, nor would it be a good idea to attack it with bombers, instead of fighters, from our own carriers, or MKIs with Brahmos. Other than that, the only potential target that could pose a threat to India, would be Diego Garcia. Which a gain would be easier to attack by subs, or our carriers. Bombers in IN hardly have relevance and even for IAF they wouldn't make much difference. More important are long range cruise and balistic missiles, as well as subs with long range land attack capability. That's what we should focus on and not on status symbols!
The difference in payload; a Tu-22M can carry 10 (!) Kh-15s, or similar anti ship missiles. It can decimate two task forces of a navy in one sortie. The P-8Is are mostly a recon aircraft, with modest strike capability.
Suppose a P-8I or some other recon asset (satellite or aircraft) detected a flotilla of enemy ships somewhere in the IOR or the arabian sea. Say, a battle group of 5 pakistani ships. If our own ships are not in the vicinity, and they are on the move, which means that they won't be there for long. A backfire could take off from Arakonam or anywhere in mainland India, fly supersonically to the spot, lay the fleet to waste, and return for champagne. With three Kh-22s they can maul an aircraft carrier, but as you rightly say, it is unlikely that we would face enemy aircraft carriers any time soon. But it can carry upto ten anti ship missiles, which means the ability to kill several small vessels (which we
are likely to face).
I'm not really making a case for them, I'm just saying that if we had them, we could find a use for them. After all, needs are unlimited. The right thing to do is to prioritize our needs. From that POV, there are many other things that the navy can get that bring more value for money, than bombers. Maybe that's the conlcusion the navy reached as well. From multiple sources, it is clear that the IN leased and operated backfires in 2001. Maybe they were trying to figure out whether such an asset will fit into their doctrine, and they must have realized that it did not, and so they did not pursue it anymore.
I wonder why the forces have not dedicated a couple of squadrons of MKIs for the maritime strike role, either by replacing or in addition to the jaguar IMs. The MKIs can carry more than twice the payload, to twice the distance (almost the entire IOR, with refuelling), while being able to defend itself against any aerial threat. These can be the regular MKis, not the super-30s. If the navy can call in the air force's MKIs to give them air cover or sink enemy vessels, it would greatly reduce the burden on the navy's carrier and fighters, and they could become a lot more versatile - performing not just fleet defence, but take on much more offensive roles. The IAF has only two squadrons of jags for that role, which are long in the tooth, and besides, simply outclassed by the MKIs. Why not make use of the Indian mainland as an unsinkable aircraft carrier, and dedicate two or three squadrons purely for maritime strike?
