There's a far more fundamental problem with low-frequency transatlantic services. One aircraft can operate a daily rotation to the East Coast - in theory. In practice, it allows no leeway for cumulative delays, technical problems or scheduled maintenance. If you start cancelling flights for these reasons your credibility goes straight out of the window. If you provide a standby aircraft and crew, your costs go skyhigh. If you go technical at Stansted you're limited as to who can help you out with stranded passengers.
Nothing to do with high or low fares. Some of us remember People Express, whose schedule integrity transatlantic was a joke, and ultimately cost them their market.