I supported the original conception of this as a new PI and support it now as mid-career faculty. The status quo means diminishing taxpayer returns, wasted labor in grant writing, and undergirding the soft money system. Three seems a fair number to spread bets and leave room for collaboration.
Mostafa Zamanian
RFI: Proposal to Cap the Number of Simultaneous Research Project Grants per Principal Investigator to Support More Researchers and Maximize Scientific Productivity and Innovation
grants.nih.gov/grants/guide...
NIH Funding Opportunities and Notices in the NIH Guide for Grants and Contracts: Request for Information: Proposal to Cap the Number of Simultaneous Research Project Grants per Principal Investigator ...