What public policy is served by making it easier for rich a-holes to buy multiple homes?
Red herring. Rich a-holes do not need Fannie Mae backed loans. They can buy with cash or corporate/business financing arrangements.
Those who are hindered by this rule are those who buy a second house and rent out their first house as a rental property. These are your typical Mom & Pop landlords. Unlike the corporate-run large box apartment complexes, these are the people who typically rent out single-family homes. These are the folks you rent from that never raise the rent until you leave.
Perhaps you are right, maybe we should not encourage the mom & pops. The better approach is to allow all investment property to end up in the hands of corporate entities. To hell with the little guy.
I agree with your comments on research, though. Research spending in this country (both Government and within companies) has been trimmed and focused too much on the short-term.