Well, TIL. Chalk it up to the crowd I surround myself with, but only colleagues have ever understood MTBF, so good stuff.
In my experience IT people know the term, but they seldom think of it or comprehend it in any real depth, rarely much beyond things like "how long til we have to replace the next hard drive in the RAID server?"
The "MTBF" and it's wider concepts (including MTTF -- Mean Time To Failure; or MTTR -- Mean Time To Repair; MTBI -- Mean Time Between Inspections; and even MTBM -- Mean Time Between Maintenance) are really applicable to a whole host of things, most of which are NOT simply "toss it and replace it", but are rather more related to when you need to inspect things, what range of "play" is acceptable or what level of wear is within tolerance, when filters & fluids need to be replaced, when belts should be changed, and so on.
So it affects all kinds of things, everything from the recommendation of when you should change oil and filter on an ICE engine (i.e. miles, months, or on commercial & agricultural machinery the operating "hourmeter")...
To, well the pricing of things like drills & saws -- the number of "medium duty hours" that you can expect from say the gears in a hand drill, will be determined chiefly by what kind of an MTTF was considered acceptable for a certain market and/or price point.
For example consumer grade drills are somewhat cheaper than "prosumer", and vastly cheaper than "professional" (i.e. trade carpenter grade) drills. And the reason is that the consumer models use really inexpensive plastic/nylon gears that require no lubrication (i.e. zero maintenance, but relatively short life), the prosumer ones typically use powdered metal gears (tiny granules that are "pressed" into a mold with heat & compression) that are "self lubricating" (infused or coated with a graphite compound) so they are a bit tougher and last longer but will still fail under heavy or prolonged use, and the professional grade which are made with hardened steel "cut" or "hobbed" gears (which are "heavy duty" and will last virtually forever -- provided they are properly lubricated from time to time).
And in that last example, there is nothing "wrong" with any of those products. They are each very well adapted to their intended market, made with appropriate materials & designs that will allow a reasonable sale price, and yet give several years worth of service when they are properly used -- that last is the key there.
The cheap "consumer" drills are designed for the homeowner who is going to use the thing maybe a dozen hours total (if even that) in an entire year, and so if it lasts 100 hours, well that's probably a decade or even two decades of use.
The "prosumer" models are aimed at hobbyists, woodworkers and maybe the occasional "DIY" cabinet maker, etc -- the kind of people who will use the thing a bit more intensively than the typical homeowner, but even still not for more than maybe 50 to 100 hours a year; so a product that will last 500 or 1,000 hours will again give him a decade of service.
And the "professional" machines are expensive, in part because they use more expensive components, but also in part because they are manufactured with higher standards and in smaller quantities (less production, even over a longer time span, meaning a worse economy of scale). Obviously a carpenter or electrician who is drilling holes a couple of hours per day, day after day, week in/week out... is going to be piling up not only LOTS of hours, but some pretty heavy use (not to mention probably dropping it a couple of times a week, having it get tossed around in a toolbox in the back of a work truck, etc), so anything that isn't built to last a couple of thousand hours is going to "break" pretty fast. OTOH, professionals are willing to spend a lot more for their tools, and given that they use the things regularly, are likely to be willing to do a bit of maintenance (adding some oil, etc).
The problem (and the "bad reputation" of the cheaper consumer & prosumer products) comes in when professionals attempt to use either of those products in trade work -- or when homeowners & hobbyists push those products beyond what they were intended to do, and use them in a manner that is similar to trade work: for example the guy who "burns out" a cheap consumer drill while redoing his whole basement (i.e. uses it almost continuously over 8+ hour stretches of time, multiple days in a row) -- and then concludes that it's a "piece of crap"... when in reality, he "abused" it in a manner it really wasn't intended or designed for, and he probably just hit or went past it's MTTF. (Whereas his neighbor who has the same make/model is "happy" with it, because it has worked very well for him -- drilling a hole or two every other month -- for a couple of decades, never overheating it, and not getting anywhere near it's MTTF hour count.)
The same thing is true of just about everything else. That's why you don't see laundromats opening up with "residential" grade washers & dryers. It's why professional landscapers who mow lawns 8 hours a day don't use mowers bought from Wal-Mart.
And conversely, it's why buying the (true) "commercial" quality products for the home is generally overkill. They're way more expensive, they lack the "trendy/fashionable" features and appearance that consumers want (commercial refrigerators for example not only don't have crap like "in the door ice/water dispensers", they generally don't even have freezer sections -- because in commercial applications, freezers are separate units, and so are ice-makers & chilled water dispensers), and quite frankly most homeowners would not want to make room for (much less buy) all of the separate units, but they would also get "sick and tired" of the things and replace them (kitchen remodel is about once a decade) long before their working life was over.