Currently, domestic layovers longer than 4 hours results in a broken fare and paying a fare for each segment vs. a single "through" fare covering entire ELM-MSY itin (there are separate fare filings for both the individual segments, as well as for ELM-MSY). Generally, one-way and roundtrip searches won't show such options which is why you have to resort to multi-city search. While purchasing separate fares on each segment is generally more expensive than a single through fare, this is not always true depending fare bucket availability and fare filings. Early during Covid, they allowed connections up to 6 hours on a single fare for a time due to very limited flight schedules being flown. They have reduced a lot of regional flying this summer due to regional pilot shortages and many routes that had 3-4 daily flights last year are now down to 1-2. I suppose it wouldn't be too surprising if they allowed 6 hour domestic connections again on a single fare from certain smaller stations if current situation continues.