1g isn't all that limiting. Under 1g acceleration you'll reach lightspeed in about a year, at which point you can't go any faster. A year to reach the top speed of the universe isn't so bad.
The truly limiting factor is that we don't have engines that can produce 1g for a sustained period. We can't carry and propel enough reaction mass and reactionless drives only exist in science fiction.
The truly limiting factor is that we don't have engines that can produce 1g for a sustained period. We can't carry and propel enough reaction mass and reactionless drives only exist in science fiction.