Yeah, but that becomes a caster vs. non-caster argument, which takes the whole thing sideways. Take a setting which assumes there are a number of epic-level people and threats that oppose them in the world. If the people with access to things like Wish and Shapechange on a regular basis are 5% of the epic population, that's an entirely different game dynamic than if they're 50% of the epic population.
Even if you get rid of the epic spellslingers, I think you'll find that top-tier 3E characters are significantly stronger (relative to lowbies) than top-tier 4E characters.
Take a bog-standard, core-only 3.5E fighter at 20th level, using just what's in the SRD. I'll use the elite array for stats, not that any DM I ever met actually made players use such crappy stats, but they are the expected values. I'll put 15 Str, 14 Con, 13 Dex, 10 Int, 12 Wis, and 8 Cha. Standard wealth by level.
This character wields a
+5 shocking frost falchion of speed (with Greater Weapon Focus, Greater Weapon Specialization, and Improved Critical) and wears
+5 mithral full plate of invulnerability. Other magic items include a
+5 animated shield, +6 belt of giant strength, +5 amulet of natural armor, pink rhomboid ioun stone, dusty rose ioun stone, +4 gloves of dexterity, +5 ring of protection, +5 cloak of resistance, +4 manual of bodily health, +4 manual of gainful exercise, winged boots, and a partridge in a pear tree.
Hit Points: 214
AC: 44
Attack: +37/+37/+32/+27/+22
Average Damage per Attack (including crits): 44.7.
Saving Throws: Fort +24, Ref +16, Will +14
Now, compare that to a 30th-level 4E Essentials slayer fighter using only "Heroes of the Fallen Lands," whipped up using the Character Builder. This character is using +6 greatsword, scale armor, and amulet, along with epic-tier
bracers of mighty striking and
gauntlets of blood. Feats include Heavy Blade Expertise, Weapon Focus (Heavy Blade), and the defense-boosting feats.
Hit Points: 237
AC: 44
Attack: +38
Average Damage per Attack (including crits): 60.64*
Defenses: Fort 49, Ref 44, Will 38
[size=-2]*Using Battle Wrath. The character gets +3 to damage rolls when bloodied and +6 to damage rolls versus bloodied foes. I'm assuming each of these will apply about half the time. In addition, I am assuming the character will Power Strike 40% of the time for 3d10 bonus damage, and that the character will crit on 10% of hits.[/size]
As you can see, they have nearly identical attack bonus, AC, and hit points--the 4E fighter has a slight advantage in two out of three, but nothing major. The 4E fighter has much better non-AC defenses, but will face correspondingly more difficult non-AC attacks. The 4E fighter hits about 33% harder... but the 3E fighter's "Cuisinart Strike" power, also known as a full attack, more than makes up for that.
Now consider that a 1st-level character in 3E has far fewer hit points, lower AC, and lower damage than a 1st-level character in 4E. You can see that 3E scales faster, even after you adjust for 4E's higher level cap.