...is my laziness comprising playback quality and perhaps stylus life if I just dry brush my LPs?1. Whether playing inadequately cleaned records compromises playback quality depends on the resolution of the system and the sensitivity of the listener. In mine, to me, the answer is "yes". In yours, to you, only you can say.
2. Whether playing inadequately cleaned records compromises stylus life is a question for experts. I do know that an accumulation of crud on the stylus and cantilever can impact many aspects of cartridge performance. I've inspected several cartridges that the owners thought were broken or worn out. After proper cleaning they played like new again.
3. A question you didn't ask, but should have, is, "Will playing inadequately cleaned records compromise the life of my records?" In my experience, the answer is an unqualified "yes". Whether you'll hear the damage being done by scraping unknown contaminants against plastic groove walls with a diamond blade depends on the answer to question #1, but there's no question that damage is being done - damage that could be avoided.