There is a lot more to a lost game than someone 'feeding'
I have been playing Tryndamere a lot as of late, and it takes a lot of experience to do the job correctly.
Tryndamere is a pusher and his main role is to make the enemies choose between their turrets and objectives. Every waking moment they decide if they want dragon or inhibitor turret.
Tryndamere can go 1/8, and still scale insanely well and carry the team. The problem is when players don't do anything.
Tryndamere makes them take those choices with pressure. If I just took 2nd top turret and they keep swarming with jungle and midlane and toplane coming after me, you need to do something with it.
No its not optimal when I die, but if this happens repeatedly and their turret is over half health, the problem is on your end. You not taking advantage of the lack of pressure will lose you games, regardless of how good the top laner is.
In fact, trynd could be 8/1 and if you still dont take advantage of the lack of pressure you will lose.
Pressure is the biggest thing in this game, if the score is 100/0 and your team does nothing with it, you still will lose.
Long story short, if your lane is consistently somewhere else, you have two options. A) follow them or B) take an objective. this can be Dragon, a Turret, Baron, their buffs, anything. Do NOT use this opportunity to recall unless you are still on your starting item at 15 minutes.