Just point on the statement that the water pressure is good. Don't confuse pressure with flow. The inside diameter could be greatly restricted as mentioned earlier. The pressure would still be excellent, but the flow, amount of water per minute, greatly reduced. The second opinions is not a bad idea, but you need to realize that galvanized pipe has a life span and yours likely has just about reached that point and the line is going to need replacing fairly soon even if the valve is repaired or replaced successfully. Supply lines have to be buried below frost level, and given your general location, this is likely several feet. (Mine is 5 feet) Trenching that deep from your house to the meter will take some time, and that equals money. I doubt if $1400 is at all unreasonable. Cost of material and installation labor will not be a major cost.