SAN FRANCISCO — A federal judge has branded Google as a ruthless monopolist bent on suffocating its competitors. But how do you go about creating alternatives to a search engine that’s synonymous with internet exploration?

It’s a process that may take years to unfold as Google appeals the landmark decision issued Monday by U.S. District Judge Amit Mehta. And with that kind of time frame looming, the forces of technological upheaval may make the exercise moot.