Portability and maintainability, if you want to boil it down to the core. The speed of gnu grep probably isn't portable since it relies on the kernel to do certain things in a cooperative manner, and it certainly won't be easy to maintain while staying fast.
I see the same in some of our software. One of our senior is rolling out a number of very, very fast collections based on compare-and-swap-operations, but you always end up thinking an hour or two about five lines of code. Most problem domains don't need this kind of performance, so most software teams don't pay the maintenance price and I think they are correct about that judgement call.
Part of the performance is algorithmic. Mixing Boyer-Moore and regexes isn't elementary. However, the knowledge is available for anyone keen to apply it.
I see the same in some of our software. One of our senior is rolling out a number of very, very fast collections based on compare-and-swap-operations, but you always end up thinking an hour or two about five lines of code. Most problem domains don't need this kind of performance, so most software teams don't pay the maintenance price and I think they are correct about that judgement call.