Will basilar thumb arthritis get better over time?

Not likely, sorry. Basilar joint arthritis (tmc arthritis) develops from ligament damage and laxity which impairs stability. Cartilage surfaces do well under compression but not shear forces. The instability with grasp and pinch leads to cartilage breakdown and arthritis. Many patients benefit from a supporting splint. Treatment depends upon symptoms, not severity of x-ray changes.
Pain may. Sometimes with arthritis the pain will burn out. The joint will still be arthritic, but it may not bother you much. This won't always happen, but it emphasizes that surgery is for when the conservative treatments are no longer effective at controlling pain.
It depends.. It depends how much you use this delicate joint - repetitive motion injury is most common cause - lie texting, computer work etc. Initial treatment is ice, rest, splint, possible antiinflammatory drughs like ibuprofphen or simillar.
Natural progression . Although symptoms may change for better or worse the natural history of an arthritis joint is to worsen over time. Hoever sometimes this means decreased motin and pain subsides. In the thumb this is less common though and decreased motion at the basialr joint if positioning is poor, causes the adjacent thumb joints to fail as well. The time frame though is very variable, genetics, luck and.