QUOTE (bibliophile20 @ Mar 9 2008, 06:44 PM)

Levitate: loading cranes go bye-bye.
Shatter/Demolish: wrecking cranes are gone.
These two examples won't work very well. Levitate has a weight cap based on successes, and can't lift anything so heavy that a pair of burly trolls can't lift it easier. Alright, so you can lift it 200 feet in the air, but you won't have the dexterity to secure it properly. So that is pretty limited. Shatter has a huge drain code, which means you can blow a wall, maybe two, before you're out for the rest of the day, whereas a wrecking crane can go all day (and now, with better sensors and so on, probably all night too).
A mage is useful in the construction industry in that he's sort of like a swiss army knife. Drain means he can't do any particular activity well or for especially long, but he can do a LOT of activities without any specialized equipment. Need a trench? Don't bother getting a trencher, your mage can do it. Need a single wall out? Same. Need the copper extracted? He could write up a spell for that. Need to tie together two wires which you can see down a ten foot hole? Mage fingers. But in any case where you're doing the same activity on a large scale or over and over, you'll want the actual equipment.
Magic allows people to do a lot of things which are very difficult to do now. Catalog, sterilize, and otherwise determining patterns, gathering data, and doing very fine work over a large area are all trivially easy for a mage, but time consuming for anyone else. As has been pointed out, object resistance means a mage can instantly sort between processed and unprocessed goods. The fact that spells can be attuned to a particular object or substance means things like extracting minerals from recycled computers, currently a hugely expensive process, becomes easy.
Astral perception/detect truth/whatever is great for any sort of job which requires interview skills, such as hiring on new personnel.
If you allow 'create foo' or whatever, then it really is hugely powerful. If you can create food or create water, you can also create compressed hydrogen or unrefined gold. Imagine for a moment if you had a mage who once a day could create half a pound of gold. Current prices, that's about $8,000 in a single day. There's a reason why I ban all 'create' spells in my games.