Indeed, but would they really be predicting future top 5 and top 10 next year?
Golubev won a 500 in 2010. Look at him now. Flash in the pan, as it so often is. One tournament doesn't make a top player, a year of consistency does. And several years of consistency make the very best.
But no-one is saying he is already a top player, nor that he will definitely make the top 5. Most people are just saying the potential to be top ten eventually, and a reasonable chance of top 20 next year. I can't recall seeing anyone say he's likely to be top 10 (never mind top 5) next year. Predicting someone could potentially be a be top 10 fully accounts for the fact that it might not happen. There doesn't even need to be a good chance of it happening - just a vaguely plausible possibility.
It's a bit like everyone who was saying after the US Open that Andy could potentially be number one by the end of this year. He won't be, and the odds were long even then, but he still stood a chance, and a much better one than Nadal, or Ferrer, or anyone else except for Federer and Djokovic.