Nowadays, the cheapest 4L.coms is lower than $100 and 4L.coms without a,e,i,o,u,v is lower than $200.
But the price of 3L seems stable and not go down.
The decrease of price of 4L do not have influence on 3L. coms ?
You'd be hard pressed finding people sell their 4 letters for under $100 if they have any long term view on them. The 3 letter's are a different animal, considering the number of them in comparison. I wouldn't view them as having direct influence on one another...it also depends on what the 3 letter / 4 letter COM is that dictates its potential. IMO