The harder problem is what you do with the result of the crawl once you have it. You need to index it. This is one of Google's deepest moats. Being able to serve any of hundreds of billions of documents in milliseconds requires an enormous amount of infrastructure and hundreds of careers worth of difficult software engineering.
I don't see a good way to split indexing out as a separate company from the rest of the search engine. It's tightly integrated with ranking. Generally a new ranking technique requires some new information to be associated with each document in the index, e.g. some precomputed scores that describe the document's quality or fitness for different kinds of queries. At query time, you're often just weighting and comparing these scores across documents.
If you had Google's index, you'd be a long way towards being able to replicate Google's results, but I don't think that would lead to the kind of innovation you're hoping for.