Crawford managed to beat Spence by TKO in Round 9, of course, this fight became history in the world of boxing because Crawford won the welterweight title and has an undisputed world record in two divisions.
Clearly, Crawford was the one who win that fight after the knockdown in the second round and from that, it's all obvious that he will gonna dominate him through the rounds. no wonder why they delay the fight till now because they know they only have a slight chance to win against Crawford. not it's clear that he is the strongest welterweight in this era and I don't have any candidate for him unless Inoue will dominate every upper weight class until he reached him just like how Pacquiao does in his prime.
Right now, I also don't see an opponent who deserves or can dominate the fight at welterweight and it looks like Crawford will be the strongest for some time to come.
Inoue is now at junior flyweight, junior bantam and batam in 3 different classes. Inoue has managed to become world champion in all three classes and maybe he can catch up to welterweight but it will take a long time if he wants to beat Crawford.