Money = spins
1 play doesn't do much, except for boosting the ego.
It doesn't matter how good you are, unless you choreograph a massive call-in WHILE you have a record representative in town for you it might make a budge if you are an unknown. Usually the record label will call the stations and look into how "real" a call-in was, and if there is continuous support for the song. If you have a song that is played and it can be tracked officially by AirCheck you might make headway. That all involves significant investment.
Radio promotion is big business, undercutting a lot of the small people. A song in the USA usually has 1 million dollars in independent or label promotion behind it, depending on how the record company splits the costs between its own in-house department and the indie promoter that is subcontracted.
I could get into specifics if anyone desires.
Sincerely,
God