It doesn't matter whether Trump's base liked his press conference
All of this is beside the point.
Like any president, Trump has a large base of people who will always like him and a large base of people who will always hate him. In Trump's case, the latter group may be larger than normal. But neither of these is the groups that will decide his fate.
Trump's presidency lies in the hands of the Trump-curious: The approximately 15% of Americans who dislike him but tell pollsters they think he might do a good job. A lot of these are people who voted for Trump despite having an unfavorable view of him.
With these voters on his side, Trump can wield a fearsome coalition that will help him retain Congress in two years and persuade Republicans and Democrats in Congress to bend to his agenda in the meantime. Without them, he is unpopular and ridiculous.
The Trump-curious do not "eat up" whatever Trump does. They are guardedly optimistic about him (or were, a month ago) and hope that he will deliver positive change in their lives.
I doubt Thursday's press conference did much to move public feelings about Trump either way. The Trump we saw is one we've seen a lot before. But it also wasn't a brilliant strategy to remind the Trump-curious why they voted for him.
If Thursday's performance imposed a cost on Trump, it was because it did little to convey the messages that he is busily working to create good-paying jobs for Americans, or that he is breaking the logjams that have made Washington look so dysfunctional to so many, or that he is restoring whatever voters feel is lost in their communities.
Put another way, the biggest problem is not what he said, but what he didn't say.
He still has time to deliver on the hopes of the voters who took a chance on him. But the idea (either triumphant or defeatist) that Trump can build the public support he needs simply by attacking the media and playing on his hard-core voter base's resentments is incorrect.