>In the long long term, isn't it reasonable to assume that Earth may end up losing mass due to space launches?

No. It is much more likely that Earth would become a long-term importer of space manufacturing for quite some time. It is much cheaper to drop stuff down into Earth's deep gravity well than to hoist it up into space. Pretty much everything in orbit (except for the Moon and mass where the Moon's gravitional influence dominates) will eventually come back down to the Earth's surface, too