Almost everything can connect almost everywhere. What you need is to set out a strategy. Set a symmetry minute, designate nodes, start writing the timetable around it, and target your investment at the stations which need extra capacity to handle the concentrated departures and at the lines which have sectional running times which just exceed 28/58/88 minutes.Everything can't connect everywhere
The biggest reason why we haven't got this in the UK is that no one in power has said "yes, this is what we want to achieve, make it happen". Start the process and in 30 years you'll rival the Swiss.