With the success of steam deck, Sony is having delusions of grandeur. They should have always kept one foot in the door but bailed on handheld market and wastes time and money on psvr. A proprietary device just wont cut it in this market and imagine arrogant Sony would have learned nothing in all these years. Don't forget, "in a few years" from now the handheld market will be even more competitive with likes of SD2, Switch 2, etc....
It's always how Sony operates, they are always late to the party, or bail out, or never finish something properly and refine the experience enough for people to choose them first or make Sony devices among their top selections. The company has a serious lack of vision, but also as I noticed with almost all their products they sell: They don't use their own products, as is evident from their Noise Cancelling Headphones or other products. They always have a terrible user experience and features that cannot be disabled, and even if they have a toggle to disable/enable them, they often don't work, etc.
And this is the same problem I foresee for their handheld: It is competing with too many, already superiour alternatives and Sony fucked off from the handheld market a long time ago instead of further investing into it and perfecting it, they let other people do the job for them. Now, they believe they can jump back into it, but they don't even know where to begin.
Nintendo does what Nintendo does, which is extremely low-end hardware sold at markup prices with good first-party exclusives, which is how Ninty makes cash. The other competitors go for medium-end/low-high-end hardware with an open system and thus have versatility. Sony has neither of these. Their first-party lineup is mediocre at best, and even if some will disagree with me on the quality of their first-party lineup (which is subjective anyways), nobody can disagree on the next part: their first-party lineup is meagre. They simply don't have enough first-part titles in their lineup to justify the same exclusivity for their console that Nintendo can & does. And again, those that are in their lineup just aren't as highly regarded or remembered as being good as Nintendo exclusives, it's just the reality of it. And then the next problem: They also cannot compete with the versatility and open nature of the SteamDeck or its alternatives.
All in all, this product will likely flop and they will abandon it again due to it performing bad in terms of sales, because they don't realize what the market wants and needs, they just try to copy someone else's success without understanding what made it succeed in the first place, and for both the Switch and the SteamDeck, the reasons are vastly different, and Sony can cover neither of those reasons, but knowing Sony, they are also too afraid to do anything new and find their own success strategy, simply wanting to emulate the success of others as many cowardy businesses that don't understand their customers do.