The fact is that managers IRL don't have access to the sheer level of help that FM players get.
Everyone on these boards can check the GPG for ideas on who to sign - with help from people who have checked the editor to find out which players will be the best; information that Billy Davies (to name one unfortunate example) doesn't have access to.
Or they can check T&TT to find out what the perfect training schedules are for certain players/teams or to find out which tactics work with the match engine. Information that Kevin Keegan (to name another unfortunate example) doesn't have access to.
Is it perhaps too easy to bring better players into your squad? Probably. But SI have coded it so that AI clubs will look for players and if no-one was looking at the 30-goal-a-season striker you signed for free, that's probably just good luck.
Is FM too easy? Maybe. But sometimes - and I'll never forget the 6 games with which I tried to save FC Kobenhavn from relegation and failed due to some horrible luck - it's also excrutiatingly hard.