Well, we don't conclusively know that. The only wizard we've seen anywhere near high tech stuff is Harry, and we know he's not a fair representative for all magedom.
Not conclusively, but...
If you plan to create a simulation of a literary world it often helps to look at examples from that world and build your simulation around that. With each book Jim adds a few new twists and elements to his world, but as a game designer that can be dangerous because it might not fit the big picture.
For example, look at Middle-earth:
1. Tolkien no longer can add to the world, so the picture is more clear. At least he can't change his mind.
2. Like Harry, Gandalf may be an exception to the rule. In Middle-earth this is because maiar (like Gandalf) are sort of like angels and each sems unique (the 5 wizards had differing abilities), plus Gandalf has one of the three great elven rings to assist him.
3. Gandalf has certain types of magic (fire, for example) but we notice that most of his magic is subtle and changes a process rather than crazy blasting magic. To use a "traditional" spell system for Middle-earth with a gaudy spell list, certain number of spells per day, and so on, would strip much of the life away from wizards in this world. That's just not the way they operate, so running a game that way doesn't work right. Would we want a "first lavel maiar" in the game?
Harry's world can be looked at in much the same way:
1. Jim clearly isn't dead and is still writing, so he may be adding twists as we go. This world still evolves, which makes our simulation very tricky.
2. Lots of people say that Harry is the exception, but in what way? Are all wizards different, and if so just how different? Harry has access to some non-traditional magic (for his world) and so we may not ever know how much is Harry and how much is the other stuff.
3. We have seen no examples of magic style X, but it may pop up in the next book. We don't want to rob the setting of its flavor, but if Jim doesn't use something we should be careful before we assume it should be in there.
So ... in my opinion we use Harry as the main template. Wizards mess up technology. Could there be a techno-mage (for example)? My answer is "no", unless Jim decides to put one in. In that case, we revise the model.
Just my two cents.