I don't think Valve is trying to convert console players. I think (and they've implied) that they're trying to offer what a lot of Steam Deck buyers have been asking for: a more powerful Steam Deck that plays more of their library. That they took a lot of cues from consoles in terms of packaging and design is really more about "the living room" than that specific customer they're targeting.
I could have consoles, and I choose not to because I have a large Steam library and, as OP said, they've earned my trust.
Valve hardware is niche. They have (as of 2024) less than 400 people working there, and surely most of them of Steam and... maybe some games.
I really heard nothing in their presentations and interviews to suggest they have grand aspirations of shifting 10s of millions of units. The Deck I think is considered a success, and still only moved in a few years what the Switch did in a few months.
I think their target demographic is PC gamers who are just not super enthusiastic about the endless hardware grind.