There are pleanty of agencies maintaining legacy code bases. Some buy them for that reason alone.
That's true, and I've maintained a few legacy code bases in my time at an agency. However, the work is still contractual in nature, and maintenance/legacy agreements typically have concrete end dates as opposed to being indefinite as they are at product shops.
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.