I am not a lawyer, but I did work on software to create trademark search reports in the 00s. You absolutely can open up a Comcast barber shop, by the existing

I am not a lawyer, but I did work on software to create trademark search reports in the 00s. You absolutely can open up a Comcast barber shop, by the existing trademark laws. But every trademark lawyer worth their retainer would recommend that you not do that. In order to be a blanket trademark, you have to be instantly recognizable in every household in the US, and be registered for nearly every possible business category. Something like Disney qualifies, because it puts its kraken tentacles into everything, and sells many types of merchandise in its giant web of internal cross-promotion. About the only thing I would even attempt is (without searching the trademark database) Disney Firearms Manufacturing, and I'd better not have more than two ovoid shapes total in my entire factory. Those, I could mine tons of brass out of, for shell casings. In addition to the law, there is the unwritten "better lawyer rule". And that means that any company that has enough money to hire more than one dedicated, full-time corporate lawyer will almost always beat you in court, even if the law is on your side, because they can tie you up forever with procedural rules and dirty tactics, until you run out of money and are forced to concede defeat. In order to win against Comcast, the judge would have to be on your side, but judges are supposed to be impartial, and those who aren't are more likely more partial to the ones funding their judicial retention election campaigns. So any sensible person, not just your lawyer, will advise you not to throw rocks at giants. But the law would still be on your side, even if no one in the civil courts system is. Though everyone who knows you would think you're crazy, and would try not to stand too close to you in public.