Why would Milton Keynes be a more attractive destination than Oxford?

People could travel there to connect with other services and destinations plus this service would allow people to avoid have to travel across London or even changing at Birmingham new street etc
Taken to extremis, this is a pretty good - err "CrossRail 3"
Weymouth
Dorchester for Poole and Bournemouth
Yeovil Junction Lower Platform for Salisbury - Exteter line
Castle Cary for Taunton, Plymouth, Cornwll
Westbury for Reading, Newbury, Bath, Bristol
Chippenham for Bath and Bristol
Swindon for South Wales and Gloucseter
Oxford for Banbury and Leamington and for Worcester and Hereford
Bicester Village for Bang & Olufsen, Barbour, Beauté Prestige International, Belstaff, Benefit Cosmetics, Bonpoint, BOSS and many more
Bletchley for Northampton, North West, North Wales, Scotland
Bedford for Leicester, Derby, Nottingham and Sheffield. Also for Luton
Sandy for Peterbourough, Doncaster, Leeds, York and Newcastle
Cambridge for Kings Lynn and for Ipswich and Harwich
Norwich for Cromer, Sheringham, Lowestoft
Great Yarmouth