Well, it's not an improvement, it's just a different design-choice. I for example much prefer Bash's way of doing it.
Also, Bash does have a way of doing it the Powershell-way, if you want that, as others have commented.
Which is also why I disagree with your statement. Bash may be old, but neither the underlying technology nor the use-case changed much in that time. So, there is not a whole lot where you can innovate with a new tool, at least not for such basic tasks, and instead, Bash has matured throughout 27 years to perfectly fit that underlying technology and use-case that millions of people have.
Also, Bash does have a way of doing it the Powershell-way, if you want that, as others have commented.
Which is also why I disagree with your statement. Bash may be old, but neither the underlying technology nor the use-case changed much in that time. So, there is not a whole lot where you can innovate with a new tool, at least not for such basic tasks, and instead, Bash has matured throughout 27 years to perfectly fit that underlying technology and use-case that millions of people have.