Two things:
1. "In a team environment" - I highlighted this because I think there's something about that idea that I'm missing. I have a gut feeling that this is what keeps the game from becoming unbalanced... but I'm not sure how or why. ("Balance", to me, means: all players, over the course of the campaign, have regularly-occurring, meaningful choices to make.)
Much has been made of the wizard's great powers. However, wizards have significant vulnerabilities. Sometime's the wizard's best move is casting D-door to escape from a grapple. Sometimes wizards get taken down by large damage.
As powerful as a druid's pet or a wizard's summon may be, a fighter is even more powerful. As powerful as a self-buffing cleric is, a fighter buffed by the cleric is even more powerful.
In order to shine, both the fighter and wizard need support of other players. However, since's the fighter's contributions are often almost automatic (just having more hit points and being in front is a good start) it is a little easier for the wizard to purposefully steal the spotlight. And yet there are games where the fighter is the spotlight stealer, monopolizing the caster's powers in order to receive powerful buffs, then delivering the big hits.
3e has shifted things slightly toward casters (clerics with full casting, wizards with easy access to scroll) yet the fighter remains viable. The problem is not raw power, but what in Shadowrun is called the "decker problem." The decker is basically a computer hacker, and while he is doing his thing, it's possible other characters may be left "standing guard." The wizard's ready access to knock, dispel magic, and fly mean that adventures can, and therefore do, make use of obstacles such as difficult to open doors (which only a wizard or a concentrated rogue is likely to be able to handle), magical traps and barriers, trange monsters, and physical chasms and other barriers. If the wizard weren't there, the fighter would just do something different, but since they are there, the fighter "stands guard" while the wizard casts a spell. While almost all characters have something to do, most turns, in most fights, not everyone is equipped for specialized obstacles.
OTOH, give the fighter the Leadership feat and an adamantine mace, and he becomes an effective problem-solver, too, in the wizard mode. Now, when the party comes upon a locked door, the party "stands guard" while the fighter smashes it to pieces, and when they need to sneak past enemies, his sorcerer cohort casts invisibility.
2. Does the wizard really have fewer resources? He can draw on scrolls and magic items of his own devising, specifically tailored to meet his goals (and add some "just in case" items). This won't be the case if the wizard has limited GP + Time (system resources the wizard needs to draw on), but a campaign with no downtime + GP seems to be a pretty specific one.
Short answer, yes. Even stacks of 1st level scrolls are a significant expense until very high levels.