Do you think it's possible that what heists are going to be was misunderstood by GTA players from the start?
I think it's possible that heists were only ever supposed to be, what they were stated as being by R* - "Heist Missions". My interpretation of that is more missions alongside the Contact Missions we already have (just with a heist aspect to them). Not therefore some significant alternate job/game mode that sits alongside DMs/Missions/Races/etc...
On the basis that the above is true, why have R* delayed them so much?
Was the fact that players were expecting something much greater than what R* knew was coming, something to do with it? Did they feel obliged to meet players expectations of what Heists were going to be, so they scraped what they actually had ("Heist Missions") and re-branded something else as Heists, something that would have come out later on anyway (eg Cops 'n Crooks)?