There is also the situation that someone gets hired for their tech skills, but the thing that keeps them in a job is their ability to pick up the domain. The tech choices are often point in time decisions which are irrelevant to any outcome. The domain knowledge builds is worth more than any framework knowledge.

If you are successfully (i.e. the business or product keeps being developed) you still need to be aware of the internal weaknesses of your original choices and the external opportunities of updating to something more modern. The challenge is in managing the transition which is a skill in itself.