I have over 27K followers, I follow less than 500 (and usually trim it down to keep it closer to 300). I too try to respond to **everyone** , but I do miss a lot and often just due to the numbers messages get lost in the influx. But I do try.
Thing is, I dont think i need to make what I say private just to avoid the asymetry, that seems silly too.. Besides if anyone engages me and is productive I will often follow anyway...