My observations:

Existing companies do tend to (but not always) stick with their legacy stack. It makes sense, it’s the safe option.

Start ups OTOH, have the freedom to choose a new and innovative stack and often do. Sometimes it works, sometimes it doesn’t. The ones that survive and thrive will likely be dated in another decade and be seen as the old guard with legacy stacks.

It’s the circle of life.

Agreed.

I also would like to add that a lot of old tech is reliable and limitations are well known and accounted for. New tech has inherent technical risk, you don’t always know what you are getting and behaviour can be unpredictable.