What town are you considering? Some areas have lost value while others are flatlining.
Relo packages vary from sponsoring company to sponsoring company. Your agent should be able to find out how much the seller paid for and owes on the house and perhaps this is the problem- they may not have enough paper equity to close at the price you want to pay.
It also sounds as though they are hoping the spring market bears some fruit.What is it they say about a bird in hand.......
Often times submitting an final offer- good till cancelled and waiting it out is the best strategy, if the current ask is not defendable with facts.
I am aware of a similar situation on a house in my town, last year. Interestingly, the owners also relocated to Texas. The house began its long jouney in the low $600's. It eventually sold in the mid $400's, far less than anyone thought it would sell for. It had become the stale donut of the neighborhood and had it been priced right to begin with it probably would have sold for $100K more than it did, early on.
This had nothing to do with market conditions. This was a seller who thought his place was worth more than anyone else did and his number could not be defended. And eventually, the seller had to let go.