I don't think there is any doubt whatsoever that expanding Anfield was the 100% correct decision, and that's even based on (IMO) the capacity being capped at 61k for the long-term. The only hope for any further capacity increases is going to be safe-standing on the Kop, which in theory might bring it to 65k someday. I see no chance at all of the Kenny or Kop ever being expanded or rebuilt. Rebuilding the Kenny would cost at least as much as the Main but for how many extra seats? Barely 5k. Likewise for the Kop. And to say nothing of the residential or infrastructure issues behind both.
But all that we have got, for £180m, is fantastic. That's less than a Neymar. And we get to stay at Anfield, which while maybe not as fancy a stadium as Spurs', will still IMO have the best atmosphere on the really big occasions due to how tight it is plus something that Spurs and City will either never have or take decades to get - history.
Even if we could have built a new stadium like Spurs, while it would probably have been 25% cheaper in the NW, at the same time it won't generate the same hike in match-day revenue due to the London factor. So expanding was the right call in that regard too.