The U.S. Department of Defense wants to increase active duty U.S. Army Special Forces strength by about a third. In particular, they want to add 90 A Teams (or ODAs, short for Operational Detachment Alpha). Each ODA has a full strength of a dozen operators, and many have not been at full strength for some time. But Special Forces are resourceful, and often break ODAs until into even smaller groups for some missions. ODAs, no matter what their strength, are the most accurate way to calculate Special Forces combat power.
The U.S. Army did succeed in increasing the number of Special Forces school graduates to 750 (they achieved this a year ahead of schedule, in 2005, when 790 graduated.) The SEALs have been less successful in expanding their numbers, partly because SEAL training is even more difficult than the Special Forces. Moreover, SEALs tend to spend more time away from their families, because they are often stationed at sea. This creates more family pressure to get out of the service.
The losses to combat, and high-paying civilian jobs have not been high enough to make a serious dent in strength. Combat losses have actually been lower than in regular infantry units. This is normal, because the Special Forces are much better trained, and more often have the initiative. The departures for more lucrative civilian employment has gotten a lot of press, but its impact has been exaggerated. The biggest problem with expanding the SOF (Special Operations Forces) is that creating new units requires more than capable recruits passing strenuous training. You need experience, and that takes time. Experience comes more quickly during wartime, but it still takes years, not months, to produce operators performing at high enough levels to be effective in a wide range of missions.
As useful as Special Forces and commandos are, they cannot be expanded quickly. It takes years to select and train these operators, and the number you can get per million population (perhaps only a hundred or less) appears to be limited.