Newsflash: Looking to buy a Long Beach NY house, seller refuses to honor initial “move out date”

So I am in the process of buying a house in Long Beach NY. It’s a very seasonal town, great in the summer. Obviously with June around the corner, I want the closing process to go quickly so I can be in the house by summertime. When we viewed the house, the seller’s agent told me “the best part is, he’ll be out of here by June 15th!” then, a few days later she told my agent “okay so he’ll be out by July 1st but that still leaves you the whole summer!”Now, after all negotiating has been done and a pre contract was sent to my attorney, they requested an “on or before 60 days” period, which I said absolutely not to— that means he could be in the house until late August. I pushed for my attorney to tell them I won’t settle for anything later than “on or before July 7th,” which is an extra week from the July 1st date we were told. This is perfectly reasonable, they’re not moving out of state, and they claim they have a house already that they’re moving to (which we’re not sure the validity of that since NOTHING is packed up in the house at all.) They are refusing to budge now beyond “on or before 45 days” which still theoretically could allow him up to (or more) 75 days before moving out. That’s august already, the season will be winding down and yet I will have paid a premium price on a seasonal house when I barely got to use it.. I have threatened to walk, as in my opinion I think it’s pretty clear the July 1st date they’d mentioned was just a false incentive to get somebody to sign, and he fully intends to delay the closing as long as possible to have one last summer with the place while still charging an inflated price for the summertime..I am an all cash buyer, I made the only viable offer on this very expensive house that will likely be hard to sell especially after the summertime, so I am at a loss for words that this guy will throw away the deal and see me walk just because he wants the house a couple extra months.Can anyone give me their thoughts on this situation? Are my worries likely accurate? Should I run away from this?