You can blame John Watts the then Conservative MP▸ for Slough and a junior transport minister at the time of privatisation who said something on the lines connections won't be held under the new regime
Actually I would "blame" a lack of communication between the various Train management/station staff for not (apparently) talking to each other and using a little commonsense and discretion in holding the train for a minute or so if they knew there were passengers on the late running incoming service who needed to make the connection and faced a lengthy wait if they missed it......it would only have taken a couple of minutes max for Goodness' sake.
"More than my jobsworth mate"?