I still think it's so cool and when don't we have air supremacy? That's who we are and what we do.
The problem is when was the last time we fought someone with a real air force? One that really tried to stop a US bombing campaign? One that had a good integrated missile/gun/radar network?
The last time I recall that being the case was December 1972, and we lost 9 B-52s, 3 F-4s, 2 F-111s, 2 A-6s, and an RA-5, in just 12 days of combat. If you go back to the May-October timeframe, you can add another 104 aircraft lost in combat, worthy of note are the 36 attack aircraft lost during this phase, all fast jets, A-7s, A-6s, or A-4s. (The A-1 Sandys had been retired by this point)
I picked Linebacker and Linebacker II as representative of the US versus an integrated Air Defense as this was the first time all of North Vietnam was fair game.
Other examples of having air supremacy but still suffering heavy losses in attack aircraft, look up the War Of Attrition and the Yom Kippur War. The advancement of surface to air missiles and simple radar directed AAA, have made "low-and-slow" a recipe for failure.