I find this as well. Almost impossible to trade for top players. I've worked for Richardson, Harvin, Dez and D Thimas this offseason and the answers have been, "I'm not interested in trading them". That's it.
Good owners are all after the same small group of players. The list changes from year to year and everyone has their own slant on things, but right now I'd say these guys are the trendy buys in general:Andrew Luck
Robert Griffin
Colin Kaepernick
Aaron Rodgers
Cam Newton
Trent Richardson
Doug Martin
CJ Spiller
Julio Jones
AJ Green
Demaryius Thomas
Percy Harvin
Dez Bryant
Rob Gronkowski
Jimmy Graham
There might be a few names missing. You can make a case that guys like Calvin, Peterson, Rice, McCoy, and Charles should still be on here. Someone like Blackmon or the Wilsons might be on the cusp. And if you're in dev leagues, a guy like Marqise Lee already qualifies IMO. These are the players that every owner in your league would like to have. It's not surprising that these players are expensive. They should be.
Smart owners are going to try to collect as many of these guys as they can. If you own players like this, they're going to try to pry them away from you using a combination of inferior players, aging stars, and draft picks. If they already own players like Julio and Green, they're not going to sell them unless they're getting another player of that caliber back. Meanwhile bad owners are going to punt these guys away for smaller pieces.
If you want to build a real monopoly, the goal is to get as many of these guys as you can. That can be easier said than done for reasons that I already mentioned. Often times, the players of this caliber are pretty apparent all along. With the hype that they had in college and in the draft, there never should have been a buy low window for Richardson, Luck, or Green. You could have gotten them for a slight discount before they played a down from someone who wanted them to "prove" their talent, but they were never cheap. And I don't blame anyone for not trading them.
The only way to get these guys is to look ahead and either take them when they're still in college (dev leagues), trade for the draft picks that become them, finish low enough in your league to get them in the rookie draft, or identify an unexpected mega star like Graham, Marshall, R Wilson, or Foster before the hype catches up. That goes back to some of the posts I made earlier this past season.
Timing is a huge part of getting good value. You need to be on these guys before the jury is out. In most of the leagues where I have Doug Martin, Demaryius Thomas, and Andrew Luck, the reason I own them is because I paid above market value to get them before their profile really exploded. If I had waited, I would've been priced out. I only won one league this past year and the only reason I was successful is because I made a number of preemptive picks and trades that broke in my favor.
If you want to do well, you need to anticipate value trajectories and make proactive moves accordingly. That was my #1 lesson this past year. You need to be the guy buying Spiller after his disappointing rookie year, not the guy trying to buy him now. There aren't a lot of these guys out there. That's the hard part. You look at some of the trendy "next big thing" options right now like Josh Gordon, Kendall Wright, Justin Blackmon, David Wilson, Alshon Jeffery, Bernard Pierce, LaMichael James, Rueben Randle, Jon Baldwin, and Michael Floyd. Maybe 1-2 of those guys are legit. The rest will end up varying degrees of outright crap or mediocre like Maclin, Beanie, Torrey, McFadden, Felix, etc.