Well of course we don’t actually know, nor do we think it’s as simple as ‘Well we thought of it first’.  It is probably a combination of:

• Habitual Thinking When we think about someone’s details we always think of their :
  • Name
  • Address
  • Phone Number
  Most system designers have simply not got beyond that to realising that an Address is something totally separate from a Person or Organisation.
• Hardware and Software Limitations  When most existing systems were developed, the technology simply did not exist to allow their designers to do other than duplicate data between records – if they wanted to retrieve it in a timely manner.  Recent advances have meant this is no-longer a constraint.
  
  Take for example the way GEM finds out someone’s Work Phone Number.  In a conventional system this information would be in the Person’s record.  So there is nothing else for the system to do, as it already has the information.  Unfortunately the same information is also duplicated in everyone's record that shares the same information.    
  
  In GEM it first looks up who that person’s current employer is.  It then looks up their employer’s principal Address (as everyone can have multiple Addresses).  It then looks up the Address to find the associated Phone number.
  
  This means that if someone goes to a new employer the system already knows their work phone number.  In a conventional system you would have to look up their new employer’s record, find their phone number and key it into the person’s record. GEM effectively does it for you.  Similarly if you change the employer’s phone number or address it automatically changes the work contact details of all of their employees.
  
  This does mean a ‘General Entity Model’ does do more work than most existing systems.  However, who would you rather did all the work – you or your computer?  In a conventional system you have to remember who else is affected.  GEM effectively remembers it for you – so you don’t need to.
  
  This is particularly important in a multi-user system, as you may not have put the original data in, in the first place.  So how are you expected to remember it?  The answer is of course you can’t.  What happens is you end up with differences in data between people’s records that should actually be the same.  Then of course you loose confidence in your system because of data inconsistencies – as you no-longer know which version is correct. 
  
  GEM simply leap-frogs these systems with an entirely new approach.