why can't gnumake utilize non-filename pattern rules?

[Randy Yates]

If I have the rule

% : gen%

(without a rule), make won't work - it says "no rule to build file $*".
If I say 

% : gen%
.PHONY : %

make won't work - it simply skips the pattern rule.

I want to make a dependency chain based on a pattern rule, without the
pattern rule target necessarily being a file. Why can't I do this? Or
how could I do this?
-- 
%  Randy Yates                  % "I met someone who looks alot like you,
%% Fuquay-Varina, NC            %             she does the things you do, 
%%% 919-577-9882                %                     but she is an IBM."
%%%% <yates@ieee.org>           %        'Yours Truly, 2095', *Time*, ELO   
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