The last few weddings I shot 20 years ago were digital. The B&G got two CDs with a release on them, along with a list of printers who could produce their images. Six months later, I was contacted by the parents and asked for two more CDs because theirs were "lost". The truth was that they were too lazy to burn more disks for relatives even though they were given releases and license to do so. Their disks were supplied in CD liners with my company name and the B&G's names on them. I printed sleeves at home that made a nice presentation.
Perhaps now, the ubiquitous laptop may not have a burner, but that is a purchase choice. There are major manufacturers that produce machines with burners as an option, but many choose not to include the feature in their purchase of a laptop. They can always buy an outboard burner if they need one. I have yet to see a machine that has NO usb input.
USB drives? Sure, the time will come when legacy drives will no longer work. That's not my responsibility. If I were still shooting weddings, I'd keep a copy CD (they haven't disappeared yet, despite the doomsayers) and (maybe) a copy thumb drive. Copies of my CDs and thumb drives would command a steep price. Storage of these things require space and record keeping, services that cost money. If I were still in the wedding rat race, I'd supply an elegant presentation box similar to the boxes used by jewelry stores. In large quantities, they don't cost much.
I kept NO negatives of weddings that I shot 25-30 years ago. After five years, I sent out letters offering to sell the negatives if the couple (or parents) who wanted them. In many cases, both the B&G and the parents were no longer to be found, so I burned the negatives. In my contract, I stipulated that I would not keep negatives past five years. It was rare that anyone came back for reprints after five years anyway, so those negatives piled up pretty fast. The B&Gs who never purchased reprints and who could be tracked down almost always hopped at the chance to buy them.
RE: media becoming "legacy" and no longer readable. It wouldn't be my responsibility to maintain images on current media. I wonder how many film shooters are willing to provide scans of negatives (or even have the means to do so).
Again, I have been out of the wedding rat race for some time, and people's attitudes change through the years. Relative newcomers to the industry want to be everything to everyone and really want to provide documentation and memories in style. Hats off to them.