Karthus-Nunu Funneling is The Closest I've Ever Experienced to Exploit

Not trying to rant really, but I think that this is a bit reductive to the health of the game and I think it's worth voicing.

Can anyone provide any sort of update on the health of this or potential counter?

I played against a team today (mid-silver), and we ended 47/46/80 and we lost to a karthus-nunu funneling strat which was only infuritating because it felt so cheap.

I played mid and the team as a whole spent a lot of time pushing out the wave as much as possible, rotating and ganking both top and bot in order to get as ahead as we could and got first tower mid (due to Karthus afk basically). The entire time Karthus was farming and unfightable to any player.

By the time we were in mid game 27-26, Karthus was level 18, 300 cs, and 4.5 item + upgraded boots with enough gold to be full build, while most other players were level 12 (support)-14 (mid/jg), a couple fed (our Lee was 13/5), ~150 cs and most with 2 items + upgraded boots or less. He was full build practically speaking.

In the next 10 minutes he would end the game at 38:28 with 370 cs, 22931 gold, 20/6/10

Now that's pretty late game, sure, but they took their time and my team did a hell of a job winning a few key fights that kept us in the game. But the point is they ended the game with literally almost double the gold of most of our players (double the support and nearly 2.5X their nunu who went 0/6/13 with 100 cs, 9233 gold.)

The game felt like a huge exploit, similar to experiences I've (rarely) had with cheats employed. I know that a lot of people talk about the brokenness of League of Legends but this was the first time I really felt that the game was being broken in an unintended fashion in order to win in the 5+ years that I've played. It was a severely poor experience with little to no recourse and I'm not sure if Riot has spoken or is aware of this type of abuse to the system.

As a long time fan/player it's really unfortunate that the game has become shaken enough that this is the case. Personally, I don't mind the bot lane shake up - I've been playing a lot of adcs (trist/jhin) and non-traditional (yasuo/vlad) alike and I think it's personally a little bit more interesting to have in the game. But the double smite strat to funnel everything into one player is actually abuse of the system and should be fixed.

Nunu intentionally nerfed himself so that he would die frequently, have little to no cs, and could help karthus win.

At 15 minutes he had 11 cs and was 0/3. He was almost legitimately not a player until he was tanky enough that he could provide snowball slows for Karthus. At 25 minutes, 10 minutes later, he had 20 cs.