Perhaps because the Sphere Builders intended their "Expanse" to engulf the entire quadrant and beyond, encompassing Vulcan and eventually other worlds like Romulus too. The reason why Future Guy stopped the NX-01 being destroyed in Cold Front is much more of a puzzle... Later on, the Suliban (under his direction) cause the destruction of a colony, which in turn almost sets Starfleet exploration back a decade or more. So his agenda apparently involved Enterprise still being around but not making history with every light year?But if that's the case, why did he tell Archer where the Xindi were?
or trying to control more just what type of exploration they did and where.
remember not to much later they stumble upon the romulan test of the cloak.
plus part of it was a ruse to get archer to meet fg.
some of the most interesting and popular choices over the year..
a romulan
an orion
henry archer before we found out more in the 4th season
wesley
the mirror version of kirk who somehow made it to the future after the terran empire fell.
an earlier version of daniels