To beat the Warriors, Cleveland needs to get faster and more athletic on defense. They just could not consistently get stops, which meant to beat the Warriors they had to score at a ridiculous rate on offense, which they only managed to do once for a full game.
I know you used the term "ridiculous rate" in terms of what they needed their offense to do. And I'm in agreement. Only once did they score at a ridiculous rate. But their offense played really well this series.
Cleveland scored 91, 113, 113, 137, and 120 points this series.
They averaged 110.3 per game during the regular season, so outside that 91 point effort in game 1, they averaged 120.8 points per game.
Golden State averaged 115.9 per game during the regular season, and scored 113, 132, 118, 116, and 129 in the series, for an average of 121.6 per game.
Moreover, during the season, Golden State allowed an average of 104.3 points per game, 120.8 per game during the last four games of the series. Cleveland allowed an average of 107.2 points per game during the season, and 121.6 per game during the playoffs.
When Cleveland was on offense:
- Cle regular season average scored: 110.3
- Cle last four games average scored: 120.8
- GS regular season average allowed: 104.3
- Cle last four games relative to their regular season average: +10.5
- Cle last four games relative to GS' regular season allowed: +16.5
When Golden State was on offense:
- GS regular season average scored: 115.9
- GS series average scored: 121.6
- Cle regular season average allowed: 107.2
- GS series relative to their regular season average: +5.7
- GS series relative to Cle's regular season allowed: +14.4
So if you throw out Cleveland's admittedly awful game 1 performance on offense, their offense actually put up more points *relative to their opponent's defense* than Golden State did.
Conversely, Cleveland's defense played better relative to GS's offense than GS's great defense played relative to Cleveland's defense.
But it doesn't ultimately matter because GS was just that much better. And Cleveland needs to improve on defense, per your larger (and correct) point, by a considerable margin if they want to beat Golden State next year.