Not sure if it's true, but I've heard they won't change the rules of football due to fifa not wanting channels to stick their own ads into the stoppage from injuries etc.
Well, if that was the case, the current model would be ideal as there are much more stoppages than if the clock stopped.
Funny or not, the continuous clock is a rule dating back to the 19th century, implemented in order to make the game
less boring.
If you think about it, having constant stops in a game can make it a snorefest (some NFL games last for 3-4 hours). The 90 continuous minutes rule ensures that a regular football match never lasts more than 2 hours.
Also, injury faking is a very recent issue in world football history. Up until the 80s it was very uncommon. The most noticeable dive before the modern football era is probably the 74 World Cup final, but it was to obtain a penalty, not to waste time.
Time wasting is a modern tactic. Up until the 80s players would not fall down for an average kick to the chins.
Some factors come into play for the usage of this "strategy": the introduction of yellow and red cards in the 70s, the increase of the number of allowed substitutions, the increasingly strict rules regarding physical contact, the wide TV coverage that pans referees for not calling fouls..
Under this new paradigm, rulemakers are at a split: you either maintain a 100+ year old rule which serves as a foundation of the sport, or you change the flow of the game to tackle a more serious issue.
So they have maintained it. And so, the 90 minute rule made to speed up the game, is now slowing it down due to unsportsmanlike behavior.
Futsal is an emerging sport (under official status at least, since it has been played for almost 100 years as well), as such it is used as a testbench for possible rule changes.