It's shouldn't be cutting edge. There may be no open source library or commercial library for your needs (e.g. parsers for most telecom protocols). Your algorit

It's shouldn't be cutting edge. There may be no open source library or commercial library for your needs (e.g. parsers for most telecom protocols). Your algorithms can be client specific. There may be only awful libraries especially if you use a language in an area for which it is not designed (e.g. something like C/C++ and Websockets). And there may be hundreds and thousands of other reasons. Of course, many people use Spring/Boost/etc. for routines like data transfer and popular protocols (JSON/XML) parsing, but it's only part of big picture.