Why D languiage creator decided to NOT fix this?

[Why not?]

Every C language manual/tutorial contains well-known warning 
about mixing '=' assignment operator and '==' equality test. 
Every now and then newcomers are warned about this - and they 
WILL do such mistakes, because it's much too easy.
During creation of new language it was so simple to fix this 
serious flaw "once for always"; simply by adopting ':=' 
assignment operator from Pascal, and by leaving - as 'equality 
testers'  - BOTH single '=' and double '==' "equal" signs.

Any idea why it didn't happen? Because "it'll spare one key-press 
when typing assignments"? Was this "saving" really that worthy - 
that it was better(?) to keep that exceptionally error-prone 
solution for next 100 years (or more)?