So write your own. I'm almost always homebrewing anyway.
I don't have to

And, ditto!
In the case of a module, you aren't passing out text for players to read and then reading it to them.
Actually, I've seen DM's do exactly that: copy the boxed texts and hand them out to the players.
Think how much preparation goes into being able to achieve that illusion of improvisation.
I don't think I've said that it doesn't take preparation.
Actually, that's something else I'm very wary of: Many (inexperienced?) DM's seem to be under the illusion that buying a published module will let them get away with little or no prep-work. In my experience, that often results in a pretty bumpy session. At the very least, DM's should read the whole thing at least once before starting their first session and think carefully about the parts that the group is likely to encounter in the next session. To run a smooth session, look up everything that's ony included by reference before-hand and think about what _isn't_ covered by the module at all.
When I run a published module I often notice that I actually have to invest _more_ time to prepare for a session than when I've written my own adventure. That's because I make the module my own: I always adapt the introduction to fit the player characters and I usually make changes to the storyline and encounters, as well, to better match my campaign.
I also take the time in-between sessions to take down notes and make adjustments to incorporate the character's actions. Every action has a reaction: Depending on how the party approaches an adventure, the behaviour of their opposition may change.
Sometimes (rarely!) the authors of published adventures take this kind of thing into account, but all too often, npcs and monsters just sit around and follow their script, regardless what the player characters do.
I am not opposed to my player's ideas, inputs, and actions to affect my world/story/adventure design. In fact I typically place multiple hooks in my adventures to see which one they'll bite into, and sometimes they even get interested in something I didn't foresee and didn't deem important at all. I'm not above embracing their ideas and re-purposing these items of interest to give them the meaning that the player's feel they should have. After all, their ideas may actually be better than what I have had in mind, right? ;-)
I know full well, that my approach to DMing isn't your cup of tea, Celebrim, but I've found it works extremely well for the groups I've DMed for
