I think there are a few main reasons - one is getting to the FLO. If you work full time and aren’t a club member it means a day off work. And another to pick them up.
Some think there finds aren’t good enough. Others don’t find anything good. Some don’t know about the Portable Antiquities scheme or are shy contacting the FLO (who are often rubbish at sharing info in their finds days).
Some don’t think it’s important, or only important if its treasure. Some believe it’ll attract nighthawks or it’ll get the field scheduled.
However there are lots who do record, and record a lot, so it ain’t all bad! For the rest education and better communication would help.
However a lack of funds does mean many FLOs are at full capacity already so would getting more who wanted to record help getting more recorded? I doubt it.
Which brings me to my final point on the selectiveness of FLOs on what they’ll record. What is not commonly known is the FLOs work for the local museum unit, not the British Museum, so they are primarily directed on what to record by local priorities. So whilst PAS sets the headline criteria (pre 1650, etc.) it’s local priorities that set the selection in the finds presented. In my experience with Oxfordshire PAS they record all medieval and earlier coins, and any decent older silver or gold coin pre 1700. They record good or unusual examples of artefacts up to 1700 but are very selective! When I brought six months worth of finds in January to the new Oxfordshire FLO he was saying yes to everything then realised he had 60 things to record so had to go through again and rejected another 15. As he said he’d have recorded probably 80 (of the 100 ish items I’d brought in) in his old county, cause the finds level there is much lower. Within 3 months of starting he already had a backlog of finds.
They need more FLOs, more self recorders or more volunteers if recording levels are to increase. Or they could dumb down the records, which would be a real shame
