No, it isn't. Before the 1.29 update, the execution limit was around 300,000 JASS bytecode operations flat, if I remember correctly. Note that it doesn't exactly correspond to operations in JASS, e.g. a function call is usually somewhere around 5 JASS bytecode ops, a variable assignment is somewhere around 2-3, etc.
Now the limit is 3,000,000, which is around ten times as it used to be.
It has nothing to do with the actual time it takes to execute the script, and there's actually a very good reason for it - if a thread "crashes", it needs to crash at the same point for all players if you want to avoid desyncs. If for some reason a thread crashes at different points, e.g. Player 1 thread crashes after a CreateUnit() call, and Player 2 thread crashes before that, they would desync.