You're right that the outcome may be similar, in that trivial contributions are discouraged. But the reasoning to getting there is completely different. Sqlite's copyright.html talks about copyright, not about maintainer overload.
An otherwise overloaded maintainer of another project may probably be willing to accept individual brilliant contributions from brilliant contributors. Sqlite will not, no matter how brilliant, if the contributor doesn't sign an affidavit. Independent of Sqlite maintainer load.
A known Sqlite contributor who has signed an affidavit, and has a history of good, accepted contributions, may also start spamming trivial contributions that may lead to maintainer overload, and nothing in copyright.html will prevent that.
An otherwise overloaded maintainer of another project may probably be willing to accept individual brilliant contributions from brilliant contributors. Sqlite will not, no matter how brilliant, if the contributor doesn't sign an affidavit. Independent of Sqlite maintainer load.
A known Sqlite contributor who has signed an affidavit, and has a history of good, accepted contributions, may also start spamming trivial contributions that may lead to maintainer overload, and nothing in copyright.html will prevent that.