There were some P-51As used in the CBI theater but the quantities were low. Probably no more than 1-3 squadrons at any one time. On dec 31st 1943 it was listed that 60 P-51As total were serving in the CBI and North African Theaters.
Likewise there were two P-38 squadrons (one in India and ome in Burma?) and we can argue all week about survival rates and such but it just may be that the P-38 and Allison P-51s were being used in such small numbers as to make drawing valid conclusions from statistics rather difficult.
I mean if you only have 12 planes operational for a mission and you lose 2 you have lost 16.6%.
If you have 36 planes on a mission and lose 4 you have 11% losses.
Nobody can say if you had more of the rarer planes if they would have lost more on the same mission.
You seem to one again imply that I'm somehow playing with the numbers here, but I'm not. I think in fact you don't understand the period or the actual combat record that well.
When I talk about losses I'm talking about on a "per sortie" basis. You can look at (Allison) Mustang and P-40 squadron missions in Burma or China, as they often went out at the same time, and see how many claims and losses were made from each squadron. P-40 units suffered about half the losses in the same exact missions and made substantially more claims. Of course there are other intangibles besides aircraft design that come into play, P-40 units were often in Theater longer and had more institutional knowledge of enemy tactics and capabilities. They had also figured out the flight envelope of their own aircraft and learned to maximize advantages and minimize the effects of flaws.
But the real deciding factor with the P-51A (etc.) was apparently due to Ailerons being too small. This was subsequently corrected in the P-51B and later models.
Raw numbers of aircraft committed to a given Theater can be a bit misleading, what actually made the difference in the day to day was how many went out on sorties. So for example you might have a total of 2000 of one aircraft built and only 500 of another, but the same number of squadrons actually deployed to the battle area during the same period. Many if not most aircraft did not get sent to new squadrons but were used as replacements.
You seem to repeatedly diminish the role of the A-36 for example in the Med but they did play an important role there, they were sent on a lot of missions and apparently destroyed a lot of ground targets including in the critical moments like at Anzio. Their advantages were two-fold - speed in getting to and (especially) escaping the target area, and accuracy due to being dive bombers. The A-24 for example (Army version of the Dauntless) could hit targets accurately but would be dead meat trying to fly out of that combat zone in 1943 and 1944. The fighter bombers like P-40s and Hurricanes could drop bombs but were not very accurate, neither were the medium or heavy bombers. Perhaps this is worth getting into as the A-36 was a competitor of sorts with the Typhoon for the fighter-bomber role.
To help convey an idea of the scale of A-36 activity in the Med, here are some examples of activity over a period of ~two months involving that aircraft. Keep in mind these are days where there were usually just a handful of claims or losses on either side except where indicated:
Dec 27, 1943 ---------- A-36 unknown enemy fighter claimed
Dec 30, 1943 ---------- two A-36s on a bombing mission claimed 2 Bf 109 and a "Bf 209" damaged
Jan 14, 1944 ----------- two A-36s lost on bombing run, (one to a strange accident ** and one to unknown reasons)
Jan 16, 1944 ----------- A-36 shot down by Flak
Jan 19, 1944 ----------- A-36 claimed one Fw 190
Jan 22, 1944 ----------- 3 x A-36 on recon flights shot down by flak
Jan 28, 1944 ----------- A-36 'probably shot down by flak' (this was a a busy day )
Jan 29, 1944 ----------- A-36 claimed a Fi 156 destroyed
Jan 31, 1944 ----------- A-36 hit by flak pilot PoW but escaped / evaded
Feb 2, 1944 ------------ 2 x A-36 shot down, one by two Bf 109s pilot PoW the other by ground fire
Feb 3, 1944 ------------ 2 x A-36 shot down one by flak one 'disappeared while dive bombing'
Feb 6, 1944 ------------ A-36 claimed Fi 156 destroyed, 5 x A-36 shot down
Feb 15, 1944 ---------- 5 x A-36 shot down
Feb 16, 1944 ---------- A-36 shot down
Feb 18, 1944 ---------- A-36 hit by flak, crash landed
Feb 21, 1944 ---------- 2 x A-36 made claims for a Bf 109 each, two others together claimed another Bf 109 probable (this was a busy day)
That is enough transcribing for now but suffice to say this continued, for example two A-36 were lost March 10, five were lost on March 13 etc.
I think this gives you an idea of the fairly high level of involvement the A-36 had at this time period, without getting into details of ground targets destroyed etc. this was at the time of Anzio (started Jan 22) and A-36 pilots hit a lot of important targets a critcial time in the fight when the Allies were at risk of being pushed back into the sea. So I would argue they were actually important and did play a significant role, if only for a while. A series of mysterious accidents while pulling out of dives ares what actually ended their role as a dive bombers.
Interesting to note that at this point the Americans were still making fairly heavy use of the A-20B
**A-36 42-84067 of the 527th fighter bomber squadron / 86th Fighter Bomber group, "exploded at 3,000 ft after pulling out of a dive-bombing attack on gun positions over San Angelo in Theodice at 1535; Capt. Robert M. Dungan KIA*
* Source Mediterranean Air War Volume IV P. 495