Thanks for the FUD.

Aluminum is no longer as brittle or harsh as it was in the 80s. They've made comfortable aluminum for years, as epitomized by the Cannondale Touring and now the Specialized Secteur.

Aluminum is actually fairly versatile. They make hybrids, mtb, plush, racing, everyday, and cross bikes (to name a few) out of aluminum all the time. They can hydroform tube shapes to make curves similar to what you can do with carbon (again, see the Secteur).

Steel is fine… for some uses. However, it can fail just like any other material, it oxidizes, and it's a tad heavier than aluminum. Carbon is a bit more specialized and less robust, but significantly easier to dial in the characteristics the designer wants to emphasize. Good luck making a light-weight aerodynamic bike with a super-stiff oversized BB and a reasonable amount of comfort out of steel.

As to "what happened to steel," as already dicsussed there's plenty of it around. You can get almost any type of (non-aero) bike you want with a steel frame.

Bicycle manufacturing is far from a fat margin business; and I might add that as long as you aren't exploiting a desperate need, there is nothing wrong with companies maximizing profits. If you really want to get outraged over profits, go look up the profit margins on soda.

And really... why care? I've spent years riding steel and aluminum. Ultimately the bike just isn't that critical; it's the muscles and the will of the rider that really matter.