The team had accumulated a boatload of top picks the last few years. And their own pick is always top 5.  The way the league works, it's impossible to stay horribly bad for long.
		
		
	 
You keep saying this, so I had to go look things up....Let's clarify the "boatload of top picks" on the team.  I've gone back to 2014 for 1st and 2nd Rnd Picks for CLE.  You are correct in that they had a lot of top round selections - no doubt.  But how has that worked out for them?
Year	Selection	Player	POS	Status
2014	8 (1)	Justin Gilbert	CB	Out of the Lg
	22 (1)	Johnny Manziel	QB	Out of the Lg
	35 (2)	Joel Bitonio	OL/G	Starting LG
2015	12 (1)	Danny Shelton	DT	Inactive (Pats)
	19 (1)	Cameron Erving	C	Starting OL (KC)
	51 (2)	Nate Orchard	DE	Out of the Lg
2016	15 (1)	Corey Coleman	WR	Out of the Lg
	32 (2)	Emanuel Ogbah	DE	Rotational DL
2017	1 (1)	Myles Garrett *	DE	Starting EDGE
	25 (1)	Jabrill Peppers	S	Starting SS
	29 (1)	David Njoku	TE	Starting TE
	52 (2)	Deshone Kizer	QB	Backup (GB)
2018	1 (1)	Baker Mayfield *	QB	Starting QB
	4 (1)	Denzel Ward	CB	Starting DB
	33 (2)	Austin Corbett	OL/C	Backup OL
	35 (2)	Nich Chubb	RB	Starting RB
	16 picks in the first two rounds in 5 years.  Surely they must have hit on those!!  Four of those picks are out of the league completely.  One has been a healthy scratch for the last half of the season and will likely be cut by NE.  One is a Backup in GB.  Only the picks made by Dorsey (2017 and 2018) are still in play with the Browns - where 6 of the 7 are bonafide contributors.  Of those that have contributed, two (aside from Mayfield) are on offense. 
IMO, all of the defensive players would certainly say that Mayfield has impacted their play for the better.  He has kept the offense on the field longer, allowing them to breathe/rest.  Mayfield has put points on the board, thus giving the defense the opportunity to go play prevent and just worry about stopping a big play vs trying to make a big play every time they're on the field.
IMO, all of the offensive players would certainly say that Mayfield has impacted their play for the better.  They know what it was like playing with Tyrod under center.  Chubb wouldn't have gotten the running lanes had teams not worried about Mayfield's downfield vision and passing accuracy.  Njoku was on the verge of being labelled a bust until Mayfield started getting him the ball.  Had Tyrod stayed under center, or worse yet - Kizer stayed in CLE (gasp!) - neither would have had the opportunity to produce as they have this year.
So yes, Virginia, I do believe that Mayfield has transformed this club for the better.  And yes, I believe his teammates would rally behind and support that sentiment.