Being able to spot one of my posters a 'mile off' doesn't mean they all follow a 'blueprint' - seriously, show me the ones that follow that 'blueprint', I'd love to know what it was, cos then I'd be able to bash out posters without having to spend ages coming up with something new each time (which is the longest part of the design process for me).
I'll help you out -
GigPosters.com - Jo Foster - Hector Collectors, The - Bears, The - Ceylan Delikanli and
GigPosters.com - Q Without U - Lipsick both have the 'spaghetti writing', but are very different otherwise.
GigPosters.com - A Forest, The - Mistys Big Adventure - Thee Moths and
GigPosters.com - Esquilax - Germlin - Thee Moths - Romvelope do the same kind of thing with the text, but as they were for gigs in different cities, I figured there'd be no harm in it.
GigPosters.com - Thee Moths (tour poster) and
GigPosters.com - Thee Moths (gig poster) were a thematically linked pair.
As are these two
GigPosters.com - Microphones, The and
GigPosters.com - Microphones, The (both being halves of a larger picture of the remains of an extinct volcano, and advertising gigs by the same band in two different cities)
Finally, these two were for linked gigs and were drawn at the same time -
GigPosters.com - Thee Moths - Drug Store Cowboys - My Legendary Girlfriend GigPosters.com - Thee Moths
Out of 135 posters I've put up on Gigposters, I'd hardly say that was a vast percentage of 'blueprint' posters....and the fact that they all have little in common with designs outside their 'pair' seems to torpedo your point completely.