Considering Diamond's monopoly on distribution has always been justified as the only thing that stopped comics shops from vanishing completely after the comics market crashed, it probably won't be good.

Though they might have a bit of hope with how many comics shops have been trying to diversify their business model to "general nerdy hobbies hangout place." Though the lockdown hasn't exactly helped that sort of business either.
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Quick update: Yeah, comic shops are pissed.

Mile High Comics Reacts to DC's Diamond Departure with DC Sucks Sale

Article goes into a lot of the history and details, but the bottom line is that DC probably just ensured a whole lot fewer comic shops are going to be able to reopen their doors.