Here's a bit of irony for you:
I want to get a Trek Portland next year if I'm still bike commuting. Worthwhile investment.
I also want to get a cheap low-end bike and a decent U-lock for high-risk commuting, like going down to Baltimore's inner harbor at night and leaving the bike shackled up outside on the street for several hours. (Parents have expressed that I'll get shot or knifed on the way home, depending on the race of whatever people I meet along the way; I generally ignore this advice)
Now, for my expensive bike, it makes sense to buy something like a $150 set of Pitlocks with front and rear wheel, headset, saddle, and brake locks. Too bad there's not a lock for the derailleur or brifters but eh.
... except that's not the bike I park in high-risk conditions.
So, the inexpensive bike would ... get ... a hardware upgrade that cost me more than the bike itself.
Do you see it?