Allegorically Lord Krishna represents soul atman existing in human body and Radha mother earth. In the circumstances how can we expect an alliance between Krishna and Radha?
As the story goes ever since souls’ atmans separated from their source Brahman, God Almighty they got mired in impurities during their cosmic sojourn. To cleanse themselves of dross impurities within they wanted to manifest a body.
No sooner life supporting planets like mother earth evolved in cosmic system, souls’ atmans immediately started manifesting life forms. In absence of life supporting planets like mother earth, all souls’ atmans would keep rotating endlessly all over cosmos.
For this very reason great importance is accorded to mother earth, even more than souls’ atmans. This is also the reason why Radha comes before Krishna. The unconditional support of Radha to Krishna, of mother earth to souls’ atmans is unparalleled.
This cosmic relationship between Radha and Krishna, mother earth and souls atmans is ordained by God in which human beings had practically no role to play. The most human beings could do was indulge in spirituality and reach cosmic end of life so that soul atman within could reach state of absolute purity forever.
Everything in Bhagavad Gita must be attempted indulging in contemplation (chintan), literally we can never understand gist of Bhagavad Gita.