High/low references to the prices in both the case of the F-15/F-16 and F-22/F-35. They can both reach about the same altitudes.
They made the Super Hornet bigger mainly due to the range issue. The F/A-18A through C was and is notoriously short-ranged and a lot of ordance was lost because they had to jettison it to get home. That was the main reason for the increase in size.
The F-16 is a bit more manuverable than the F-15 but in its original form it didn't have a BVR(Beyond Visual Range) missile at all, just the AIM-9 Sidewinder infrared missile. So the F-15 could kill the F-16 at longer ranges before manuverability become an issue. Then along came AMRAAM, the first American active radar missile that wasn't tied to a single fighter.(The F-14 had the active radar Phoenix missile but it was huge and couldn't be operated by another aircraft. Essentially the F-14 and the Phoenix were designed as one weapons system whose goal was to meet a Soviet attack on our carriers at as long a range from the carriers as possible as part of a three layered defense with the F-14 being the outermost layer.)
Engines have also improved over the years and the fighters themselves are heavier as more has been added to them. The F-15's engines are powerful enough to mostly offset any manuverability issues from wieght. The F-16 now only has an airframe in common with the original. It's a lot heavier, can carry a massive array of weapons and sensors that weren't available then including a completely different radar and the Lantrin series of ground attack pods and have new engines.
Being larger also means you can mount more powerful, longer-ranged, more capable radar and the current idea in air superiority is to be able to detect and kill the enemy from as far away as possible before they can even detect you. So the smaller fighter is at a disadvantage, especially if it doesn't have a BVR missile like the original F-16.
As for the fight, something like that happened between the Isrealis and the Syrians over the Bekka Valley in Lebanon in 1982. Using good coordination, BVR missiles and AWACS(Air Bourne early warning and control) they downed 82 Syrian fighters of various types with no losses to themselves.
To even be accepted as a design over the last 15 years the fighter has to be multirole. The Mirage 2000, Eurofighter Typhoon, Swedish Grippen, F-22, F-35, Super Hornet, F-15E, all have both ground attack and air to air capability and it has been added to aircraft that previously didn't do it like the F-14, Su-27 and MIG-29 in later variants. The British are even retiring the Tornado Air Defense Variant and replacing it with the Eurofighter because it can't be adapted for the ground attack role.(The Tornado ADV and IDS[Interdiction Strike] have the same fusealage but complettely different engines, weapons fits and sebnsors. The IDS is optimized for ground attack while the ADV is a pure interceptor) Existing fighters have seen thier roles broaden immensely. The F-16 now does literally dozens of missions that weren't on its original role as a cheap air superiority fighter from functioning as a SEAD(Suppression of Enemy Air Defences) aircraft, to close support to interdiction/strike, reconnaissance, and so on.