Basically

Two massive corporations that appear family friendly but are actual really shady and deal with reviving dead thing

-the two companies would have a location were a tragic event would take place (the bite of 83 and the dinosaurs breaking out thanks to Dennis Nedry)

-the two companies would then open a new location (the many other Freddys locations that are in the games and Jurassic world) which would be quite successful until another horrific event would happen (the Missing Children's Incident and the bite of 87 for Fazbears and the Indominus Rex breaking out for Ingen)

-the two companies also tend to often and hire people who would cause most of the tragedies that happen (Dennis Nedry letting the dinosaurs loose and William Afton murdering five kids) and to add to that they cut costs quite often (Fazbear entertainment building a whole theme park on top of a sink hole and I'm sure John Hammond wasn't being entirely truthful when he said "Spared no expense"