Not necessarily the case. For years I've been making music with poor quality despite being a good rapper and a common criticism will be the quality. These days a professional approach to rap music is a must. Nobody wants to listen to a rapper who sounds like he or she isn't serious about making the best music they can. Additionally, it's a shame to have good talent ruined by bad quality. The amount of times I've found it hard to fully enjoy a song because it's been recorded from something nasty like a laptop mic is too high. That's why quality, at least in my eyes, should be of a decent enough calibre. It should at least be around the level that I have (which isn't professional at all but is pretty clear and decent)