what are the fundamental obstacles hindering Perl to be used instead of Bash and or PowerShell?

For instance I'm aware of easy piping with | and redirection >

but this could be handled by reversing the direction and aliasing some builtin commands to Perl subs

for instance ls | grep '.txt'|less could easily be less grep {/.txt/} ls

with less and ls implemented as subs (see also Shell )

What else?

Insights?

°) see also Shell and aliases in perldebug like | for paging