Finland announces migration of its rail network to international gauge

I understand why they do it, but I am curious why there is nobody in this kind of position that is going for something that is better in technical terms, not just compatible. For example, 2 meters or even 2.5m would provide better load capacity and better stability for high speed curves, while keeping the width of the carriages the same in order to fit existing tunnels. For new freight lines even 3 meters may be much better that refitting to the relatively narrow standard.

Because the benefits are negligible.

Freight-wise, better load capacity can also be solved by ballastless track, using additional axles, or running longer trains. Passenger-wise, better stability can also be solved with canting - and wider tracks means significantly larger curves.

In return you get to buy significantly more expensive one-off trains and are unable to connect to your neighbors. Not exactly a great deal, is it?

Longer trains are not a simple solution as side tracks for passing by need to also be longer. Also longer trains means building and running more carriages, which is more expensive.

Why are wider inter-track requiring larger curves? It should be the same, but with better lateral stability.