If you want the game to survive, if you want WotC to release more new material, if you think you might ever want a career, job or even a part time gig in the RPG industry, then you need to support those in the industry by buying some of what they sell.
Does a player need the PHB to play? No, the Basic Rules or SRD are enough.
Should there be at least one purchased PHB at the table? Of course. Does it need to be the DM? No. Why should the DM invoke the costs and trouble of carrying it around?
My solution was to buy Fantasy Grounds and the PHB there (and supported financially by my players). Every single player in my campaign can access the PHB all at the same time, we only need one copy. Even at full cost, $50? for the PHB digitally that can be used this way is a good deal.