The author clearly show that support aircraft just complicate the mix, and that different type of aircraft with similar role complicate logistic.
He simplify his tactical air group by using F-15 and variant plus support aircraft. The F15 and variant made up the roles of fighter/cas/interdiction/recon and electronic warfare.
Today with most multirole aircraft it is possible. Rafale can make this, super-hornet with his growler variant can, I think the newest variant of Su-27 can. In fact only the electronic warfare part is less frequent.
I would personally see several air group type:
-combat air group (fighter/interdiction/recon and lethal electronic warfare)
-support air group (long range recon / airborne radar / airlift / air to air refuelling / ELINT / rescue)
-CAS air group (Attack helicopter and CAS aircraft / medevac), even maybe giving this to ground force branch, they know what they need to support themselves better than air force.
Adding for some rich countries a "strategic air group" with long range bomber and support.
The key is, as he said, affordability, with one common combat aircraft (maybe some slight variants like growler), one or two common hull for support (MRTT + C-17/A-400 for example), a CAS aircraft and drones, you keep number high enough to lower development cost. You wouldn't avoid some small number of specialized aircraft (U2 type recon, very heavy transport...) but it would be logical and manageable for logistic.
In the future Drone will also change some things, a drone with different package can switch role between missions. Put camera you're making recon, put jammer you're blinding the enemy radar, put bomb you have your interdictor.