Skipping that part is even more ubiquitous than failure to properly torque. It takes a lot of effort to buy the correct bolts, only specialists have them to hand for a given make. Even dealers might not have every bolt. So it means you need to procure many more parts you would otherwise (the part you're replacing, plus 20 specific bolts with part numbers).. Most mechanics don't bother unless it's something really big like cylinder head bolts or an axle nut.
That is probably valid reasoning when talking about a neighbourhood mechanic dealing with all brands but it does not hold for an aircraft maintenance shop. Skipping this step makes them liable for any problems caused by failure of related parts so I assume [1] they keep to the book in this respect. Anyone here who has experience with one of these shops want to chime in? When I work on machinery I tend to follow the rules when dealing with stretch bolts since these do tend to fail far more often when re-torqued but for normal (non-stretch) bolts I do often reuse them if they're in good enough shape. I work mostly on farming/forestry equipment and our personal vehicles though, not on airplanes.
Most service manuals require new bolts, fasteners and washers for torque-critical parts.