Bullock, hello!
Well, possibly...
What exactly is the definition of "more cost-effective" here?
If strictly referring to the number of planes scrambling for ground attack missions (namely fuel consumption, ammunition spent and, perhaps, potential losses) then it´s probably more cost-effective to unleash 100 Typhoons that will require no escort (100 planes only) than sending 100 Stukas or IL-2s which might require a few dozens of fighters to provide escort. (say, a total of 120-130 planes).
100 planes vs. 130 planes? 100 is -apparently- more cost effective. Ok.
Kind of a tricky game that we have here.
The problem, however, might rise to the surface when we know of the investigations carried out by the RAF and USAAF. As the allied armies advanced further into Germany, German tanks and vehicles found either destroyed or abandoned across battlefields underwent thorough inspection.
This particular problem can have a direct impact on the cost-effective issue you are commenting. Let´s see:
The Typhoons, just like the P-47s in the ground attack mode hardly hit any tanks, vehicles or any other motorized items the Heer deployed in battles.
When targets were large concentrations of troops and vehicles Typhoons and P-47s of course did not have that much trouble in hitting the mark.
A VERY different thing happened when they Typhoons attacked Panzer and other motorized formations in motion though: hits were as scarce as water in the Sahara is; and not just that Bullock, losses were far greater for the attackers -Typhoons or Jugs- than the losses caused to German armor during such attacks. (!!)
Incredibly as it might sound, and when the outcome of allied ground attack missions is now known, USAAF and RAF pilots attacking German armor created what can be one of the wildest overclaiming precedents -in direct contest with B-17 and B-24 gunners.- They claimed the destruction of number of tanks and vehicles that simply did not exist in the order of battle of the Heer for the entire Normandy campaign.
Erich has posted priceless information in the forum regarding this issue; Niklas Zetterling is another good source.
So, launching formation after formation of Typhoons to attack enemy armor and motorized units will have as result that they will fail to accomplish the task, in any possible degree. by not inflicting sufficient losses to regard the German formation as "depleted", much less to ensure complete destruction of the enemy force.
There´s however one thing they can certainly attain: to cause critical delays to German panzers trying to reach frontlines (as it was achieved during the war).
So, one mission of Stukas (including that dozen or dozens of escort fighters) can ensure a far greater level of destruction of enemy tank/motorized formations than Typhoons or Jugs can come close to attain flying 2, 3, 4, 5, 6 or 11 missions.
In conclusion:
Depending on the mission and enemy forces present, a flight of Stukas, whether scorted or unescorted, will be overwhelmingly more efficient in either causing massive damage or complete destruction of the enemy target, while a flight of Typhoons or Jugs, even if numerically superior to the flight of Stukas, will fail to cause enough damage, if any...
My opinion on which kind of deployment could be the more-cost effective.
As additional comments:
Chances are you´ve heard of the G-6/R6 version of the Bf 109, which had one MG 151/20 cannon under each wing -in a gondola-; virtually universally depicted as either "easy prey" or "no match" for allied fighters as a consequence of the additional weight and drag of that configuration.
Well, the Typhoons in ground attack roles using non-guided rockets had a set of rails under each wing -where rockets were positioned-; from the comments I´ve collected in past years, German guncamera included, it´s very clear the rails under the wings of Typhoons were far more problematic to the British pilot than the under-wing pods in the Bf 109 G-6/R6 were to the German pilot -there are large numbers of victories against USAAF fighters attained in that particular version of the 109, but that´s an ingredient for other discussions.
So, in addition to the fact they were not good in the ground-attack mode Bullock, the Typhoons with underwing rocket-rails were not efficient if intercepted by Fw190s or Bf 109s, even after having fired their rockets.
Cheers!