I'm seeing UA fares from $507 roundtrip now for 12/18 - 12/23 for EWR-TPA ($550 from MCO). So perhaps they have released inventory in lower fare buckets again since you last checked. Demand for Christmas travel begins to really pick up the Thursday or Friday before the week with Christmas in it (the 16th this year) and from that point on through New Years, fares tend to be pretty pricey.
Even though seats are mostly empty now, revenue management knows the historical demand patterns and do not set a fixed number of seats at particular price points as they want to get the highest fares possible. If you can find roundtrip tickets on a legacy for under $400 for these dates, I'd say you are probably doing pretty well. There are roundtrip fares available from around $200 in main cabin in early December. This is due to a lull in demand for travel after Thanksgiving and before demand for Christmas travel picks up in mid-December.
Last edited by xliioper; Apr 12, 2021 at 9:45 am