My first thought on the title of the article was "if it ain't broken, don't fix it". As it goes for 'commuting' people back and forth to ISS (and previously to Mir - Mir means both 'World' and 'Peace' in Russian language) Soyuz was the favorite means of transportation. I am not against upgrading, but if it does the job, leave it alone :)
Cost is always an inseparable part of the equation however. Going to space for $10000/kg vs $5000/kg vs $1000/kg vs $500/kg all mean very different things for what missions become feasible and the safety factor and performance of said missions too (since the latter both have mass costs). SpaceX or BO ultimately doing the job much more cheaply, carrying more mass, with simpler designs made possible by modernized ME and knowledge, and that are more adaptable to other missions (methalox for example is a favorable compromise fuel for Mars surface launches and orbital refueling), doesn't mean Soyuz would be "broken" sure but it will make it obsolete for most of the world. Ground manufacturing capability and best practices change too. Long term standing still isn't a great idea.
Ref RD-107: https://en.wikipedia.org/wiki/RD-107#/media/File:RD-107_Vost...
Problem is - it's broke already. In all means - sloppy quality, price hikes, political bullshit with 'russkiy mir'...