Here are some examples of wall socket electrical outlets with USB charging connectors available in Singapore, in no particular order:
* Legrand offers some, such as certain models in their Mallia range.
* Line8, which offers custom configured "track" systems with optional USB connectors.
* Schneider, such as KB15USB_WE and E82T25USB_WE_G2.
I don't think obsolescence is too much of a problem since it's fairly easy and not too expensive to replace wall sockets every decade or so, but a potentially bigger concern is that USB connectors and cables typically aren't durable. It's not uncommon for someone to wreck these USB connectors pretty quickly.