I think its important to know that a 15 minute radiance is elite level lane control and farm and that its possible if for no other reason than to see the potential for improvement. I think most players in low tier think that the potential item acquisition speed is much slower than the theoretical max. Sutekh is wrong if for no other reason that he argues beyond the reality that every dota game is relative. If you've got 30 cs in 10 minutes that is not good in a high skill game in a freefarm lane, but 30 cs in 10 minutes in the lowest bracket of dota may as well be a god.
This is the same reason that when someone picks up dota they shouldn't be afraid of playing some carry role in low tier. Dota is a game of relativity, just look at the types of progames that occur, 1 hour farm outs with great defensive plays and 10-15 total kills and 500 cs on carries and on the flip side all out aggression games with nearly 2 kills a minute and in games like that you may still have a top total cs of around 200 by the end after 40 minutes. If you are aware that the game balance will shift as you improve and that item benchmarks are fluidly based exclusively in the game you are playing. If you make a 25 minute radiance, and is the fastest/first big item on the map relatively speaking there is a huge chance you'll end up winning if for no other reason than the farm on a hard carry will outpace anyone else on the enemy team.
At low tier, treads wand bracer at 15 or 16 minutes will put you damn close to being the top farmer in the game, by vhigh, that's like a 7-8 minute amount of farm. But overtime I think that if you're always focused on improvement and understand what's possible you'll just find yourself climbing up the skill brackets. Its a fine line between explaining to a new player what's possible, and what's passable. They are two distinct things, and they are equally important if you actually intend to get better at this game. If the fastest radiance you've ever farmed is 30 minutes, you know that's an issue. If the next time its 27, then 25, then 22, then 20 etc, you'll find yourself in a higher skill bracket from that as a consequence of attention to detail.
TLDR: Each game of dota is relative, even if sutekh wants to argue otherwise.