Currently, Polygon cannot compete with BSC because BSC still has many conveniences that people can get. However, I think currently BSC and Polygon are both in the good category. If time after time Polygon is able to provide the best, then in the future Polygon may be able to compete with BSC.
The advantage of Polygon at this time is the transaction fee is very cheap, but it still hasn't been able to make it more popular than the already popular BSC, so in general Polygon still needs time to shift the BSC so that new project developers can be more interested in using it Polygons later.
Actually the most important foundation for making devs. switching to Polygon is low cost and transaction speed, and it's already in Polygon, the thing Polygon has to do to beat BSC is to have a big exchange like Binance so it will easily beat BSC.