I've done deals before with nightmare heirship issues. I had to dig up death certificates from remote counties, get multiple, remote family members to sign affidavits of heirship, etc. AND, because of all my hard work, a title policy WAS issued. It was A LOT of work, but I got it done and made a nice profit. It sounds to me like someone just doesn't want to do all the work that the title company has told them would be required before they'll issue a title policy. I wouldn't walk away. I'd RUN away from this deal! With so many other opportunities out there, doing a deal without a title policy would be crazy. In fact, even if there were NOT a lot of other opportunities, it would still be crazy to do a deal without a title policy. BTW, it makes very little difference that the deal would be closed AT a title company if a title policy isn't issued.
The only way I can imagine that you might be able to do this deal, and only if there's a BIG potential profit, is to offer to take over for whoever has it now, get the heirship issues resolved so that a title policy can be issued, and then buy it. If they won't let you take control, move on to the next deal.