It appeared that Owen might have meant that there would be a lower bound on resale price of the NFTs, which is neither a new concept in NFTs (see Kaiju Kongz or Rich Bulls Club), nor does it mean the NFTs "can't lose their initial value". It just means that when the NFTs do lose their initial value, collectors can't recoup even a portion of their investment.
Former footballer Michael Owen claims his NFTs "will be the first ever that can't lose their initial value"
In what almost guarantees some fun lawsuits down the line, former footballer Michael Owen tried to hit back at "the critics" by announcing that "[his] NFTs will be the first ever that can't lose their initial value". Owen's business partner quickly turned up to do damage control, writing "we cannot guarantee or say that you cannot lose. There is always a chance".
- "Michael Owen mocked after making bold claim that his NFTs can't lose value", Manchester Evening News