Recent experience six weeks, four days door to door:
8 May, application sent via Thai Post EMS from Bangkok to US Embassy.
9 May, EMS tracking confirmed receipt by an embassy “security guard”.
25 May, Travelstate.gov passport renewal application status reported receipt on 22 May.
14 June, Travelstate.gov reported new passport mailed out on 12 June.
20 June (end of estimated six-week processing time), emailed embassy. Responded promptly. “Your passport is completed and is being mailed back to our office. However, we cannot advise an exact date of when the passport may arrive. You will receive a separate notification email once the new passport is ready to be mailed to the address you provided.”
21 June, embassy email received. “Your new passport book and/or passport card will be mailed within the next two working days. You are able to track your package via https://track.thailandpost.co.th/ with tracking number ######## accordingly.”
23 June, receipt of EMS with passports.