Somewhat disagree. Casters have the highest potential to usurp other class roles if they purposefully choose to do so, but rogues can usurp them too with wands and scrolls. What's good for one class is good for the other. And of course, magic items can replace ANY role, and...why, what's this, rogues get Use Magic Device?
I think a lot of the "ROGUES ARE USELESS!" comes from those tumor-ridden "intellectual puzzles" that the CharOps board liked to do, where the wizard is apparently the biggest jerk in the world and goes way out of his way to purposefully try and replace other party members. The emphasis on my first sentence is "IF THEY PURPOSEFULLY CHOOSE TO DO SO." No wizard levels up and goes "AWESOME, I CAN CAST KNOCK!"
Nope. Mine came from experience. My handle here is my longest-played character: an elven thief (2e) gone rogue (3.5) who played in a group that for a long time consisted of 3 wizards, a fighter, and me.
First and foremost, a few clarifications.
The marginalization doesn't begin until 10th level. Before 10th, rogue still shine as a viable character choice. Its 10th+ that rogues begin to loose luster. It start right around the time second-levels spells become trivial: casters aren't relying on those spells slots for Acid Arrow or Hideous Laughter, since the damage or save DC is too low to reasonably affect most CR equal opponents. Its also when most PrC bound Wizards are doing their thing, and their int scores begin to push up toward the point they have a reasonably large selection of skill points (depending on ability score-method, we used 4d6, so most mages had 16+ at start).
Once 2nd level spell slots (and first, barring magic missile) are freed, you have lots of options to start expanding into utility magic. When scorching ray is your primary damage spell, blowing a spell slot on knock is worthless. When it doesn't do enough damage to worry about, knock is a very good substitute spell-slot. This, coupled with the "no brainer" spells of higher level (dim door, greater invis, fly) still leave most wizards a good selection of spell slots still open to blow on fireball, cone of cold, blast of flame, etc.
(aside: if wizards are wasting spell slots they could be using on Acid Arrow on spells like knock, doesn't that reduce wizards to just combat magic?)
Once this happens, its a slow burn toward inevitability. Your damage potential of sneak-attack is mitigated by your overall squishiness (second only to the mage, without the benefit of stoneskin) and spells and magic items slowly replace skill checks for all but the most mundane uses.
The rogue gets caught in between: unable to offer much in combat (unless built monster-style for max SA/round) and increasingly losing much of his use outside combat.
There is one flaw in the argument though: rogues shine always in trapfinding. However, unless your DM is trap-heavy and makes many traps impossible to circumvent, their area of expertise is dubious. If your not a dungeon-heavy DM, its worse since most wizards get better chances to rest outside dungeon scenarios and the team is less dependent on sneak/recon/trapfind than they are on buff/scry/teleport.
Use Magic Device? Its the classic "If you can't beat 'em" argument. My rogue lacked UMD, it wasn't in his character (and he had three mages hogging the scroll/staff/wand list). However, I think its telling that the argument to rogue's inherent imbalance against magic is "well, then they should use magic".
If you never play past 12th level, or you have tight reins on your wizard, YMMV. However, I'm glad to see I'm not alone in arguing that magic as it was written in 1e-3.5 did a good job of replacing the skill system and trampling the rogue. Each edition did better than the last, and I'm not sure 4e got it right (time will tell).
Is it magic? Is it high-level (melee warriors seem to get edged out too, in favor of fight-ending superspells)? Who knows. But the phenomenon is real, and it doesn't require a dedicated wizard blowing his spell selections on knock and spider climb, it requires a high-level wizard who needs to fill those low-level slots with something useful when 1st and 2nd level attack magic doesn't cut it...