I don't think this is true. There were massive investments into the Ticino regional rail network over the last 10-20 years, partially driven by the NEAT extension, which shortened travel times between regional centers (Lugano - Locarno - Bellinzona) dramatically.

What doesn't seem to work well are interconnections with neighboring Italy, but that is likely not due to underinvestment on the Swiss side. Road traffic is therefore still a huge issue in Ticino, as many Italian workers cross the border twice per day by car due to the lack of adequate public transport options.