Looking into the possible futures, the Sphere Builders see themselves losing the battle of Procyon V in the 26th century. They then manipulate the Xindi into attacking Earth in 2153, which leads to the Sphere Builders' being defeated 400 years earlier than in the future they forsaw, and their long term plan of converting our space to make it habitable for themselves (i.e. the spheres and Expanse, both integral to the 26th century war and thousands of years in the making) going up in smoke.
If anything, time was changed, but it was not a loop.
The sphere builders didn't see themselves losing with certainty; they can't - they didn't see Archer destroying the spheres (the future isn't fixed in star trek). They saw the future of them losing is probable AKA NOT certain.
As for the spheres destroyed in S3 being integral their plans - in Enterprise we saw them transform space with blinding speed.
They tried it again, with a new round of spheres/their technological successor in the 26th century, this time transforming space at full speed. This time, they were stopped at Procyon 5.
Which is the only version which fits what Daniels said and the scenarists' intent (as displayed in the relevant sequences, etc).
Any other interpretation leaves you either willfully ignoring large parts of the sequences, their tone, etc ('momentous event in history', etc) or with FAR larger inconsistencies (the federation not existing to fight if Archer failed; Daniels not caring about massive alterations to the 26th century, etc).