#5 Why did Brock Lesnar wrestle a proper match against AJ Styles?

After being accused of working half-heartedly, of being a thankless part-timer and doing the same suplex-F5 routine in every match, it seemed like Brock Lesnar went out on a limb to prove everyone wrong.
Only, Brock Lesnar has traditionally never given a hoot about what people think of him. And I highly doubt that was his motivation against Styles too.
But one of the reasons why he did end up working an extended match against him could have been because Vince views Styles as a top player, along with the likes of Roman, Strowman and Cena.
And the trainwreck against Strowman must have been a bitter pill for Vince to swallow, what with him still trying to undo its ill effects.
The bottom line, however, remains that Brock Lesnar is well capable of putting someone over even in victory if he wants to. He wanted to against Goldberg and it was obvious that he wanted to against Styles too.
Also, the WWE Champion cannot possibly get squashed by the Universal Champion, thereby undermining the legitimacy of the title.
Plus it was Survivor Series, one of the traditional Big 4 pay-per-views.
So while I don't think Lesnar putting on a great match with Styles was down to one specific reason, I do believe all of these reasons may have contributed in some way to it.
Well, whichever way it is...who's complaining, right?