... print is only printing what is in the parens because it is treating that part like the complete input to a function ...

Deparsing with full parenthesization (see O, B::Deparse) shows this clearly. (Note, in addition to "print (...) interpreted as function...", the warning about the return value of print being raised to an exponent and then thrown away!)

c:\@Work\Perl\monks>perl -wMstrict -MO=Deparse,-p -le
"my $i = 5;
 print (1-1/2000)**$i;
 print '' . (1-1/2000)**$i;
"
print (...) interpreted as function at -e line 1.
Useless use of exponentiation (**) in void context at -e line 1.
BEGIN { $^W = 1; }
BEGIN { $/ = "\n"; $\ = "\n"; }
use strict 'refs';
(my $i = 5);
(print(0.9995) ** $i);
print(('' . (0.9995 ** $i)));
-e syntax OK

c:\@Work\Perl\monks>perl -wMstrict -le
"my $i = 5;
 print (1-1/2000)**$i;
 print '' . (1-1/2000)**$i;
"
print (...) interpreted as function at -e line 1.
Useless use of exponentiation (**) in void context at -e line 1.
0.9995
0.997502498750313
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