We would happily switch to more standard European gauge here in Finland, if EU would pay for it. Mostly issue is money and lack of need to change. We have train lines to Sweden, which require switching trains on border, but they aren't that hugely popular and important as Lapland has fairly low population density. Only direction that normally has really much need for trains is to Russia, which has "close enough" gauge that suitable trains can work with both rails.

It is hard to sell the changing of gauge politically when the benefits are so small. EU has some ideas about unified train network, and they aren't keen to give money for building for "wrong" gauge, but I doubt they would pay us to change the gauge and trains to European standard...