It's not that they don't have a good reason as to why they can't update their server infrastructure.

It requires physical items that literally don't exist beyond their raw components. There are select few semiconductor manufacturing plants in all of the world, and when COVID hit, auto makers cancelled their orders and a good chunk of these semiconductor manufacturers shut down (either temporarily or otherwise). Orders began to pile up from every corner due to never-changing demand with a reduced production capability, and then auto makers renewed their orders once some of the haze cleared - and then there were problems.

While expansion launches are rarely pretty, I don't think Square Enix expected a fallout of this magnitude to occur. They likely expected issues, but this is a bit of nightmare.