It doesn't matter how many so-called "weapons" you put around a quarterback. The Shiny Hood Ornament Man Law tells us that quarterbacks make wide receivers, not the other way around. And right now we have four years of evidence saying that Ryan is not good enough to make his receivers better.
Which is of course not to say that the Browns do not need to add more "playmakers" to the team - they do. It is just to say that those that bemoan Cleveland's lack of WR/TE talent versus the top passing teams have to take into account that the QB's of those teams are almost certainly making those Receivers look better than they probably are; i.e. most of them wouldn't look all-world in, say, Washington.
Let's look at the 3 teams most people regard as the top Offenses:
New England -
Wes Welker - Undrafted, 3rd team
Chad Johnson - 2nd round, 2nd team
Deion Branch - 2nd round, 2nd team
Julian Edelman - 7th round
Rob Gronkowski - 2nd round
Aaron Hernandez - 4th round
New Orleans -
Marques Colston - 7th round
Robert Meachem - 1st round
Devery Henderson - 2nd round
Lance Moore - undrafted, 2nd team (cut by Browns)
Jimmy Graham - 3rd round
Green Bay -
Greg Jennings - 2nd round
Donald Driver - 7th round
Jordy Nelson - 2nd round
James Jones - 3rd round
Jermichael Finley - 3rd round
You could argue that those 3 teams are just obviously superior in selecting talent, and there might be something to that. But it's hard to believe that many of these players would've grown into what they are had they been drafted by a franchise with a carousel at both Head Coach and QB... kind of like a team we know.
And then one would conversely wonder what certain Browns Receivers might look like if they had been drafted by one of the above 3 teams, aka a team with a good QB.
Again, not saying that the Browns WR corps is comparable to those teams... just saying that the QB situation here probably makes the WR/TE situation look worse than it is.