Long term in the WTA would be the last 5 years. TAKING IN CONSIDERATION, for example, recent very bad trends like Osaka's 1 1/2 year drought (which is explainable). Over the last 5 years, Naomi has been the best player, but we know that she looks iffy for the USO.
Short term is about 6 months. The good 6 months that Megan is mentioning about Garcia.
And, for example, very short term. Rybakina has had the best last two months of anybody. But she has returned to being what she is: a very good, top 25 player. But, as you say, I would not bet much on her doing extremely well at the USO.
But that has been the subject for this topic. Look at how little we have spoken about the ATP. We are a bit more sure there.