Fractions or they start spinning angstroms. There's always a smaller measure to adopt to support a marketing message. And don't let the laws of physics get in the way either. By super-fine hair-splitting, it can sound like whole number generations year over year while actually being only a fraction of what used to be a single generational number.
For example, if we put this in money terms, you would think a penny is as low as money goes. And yet, every gas station you pass adds the charge of 9/10ths of one cent... implying that someone else might bid that down to 8/10ths, 7/10ths, etc. But what if it gets down to 1/10th... then what??? Hello .0099, .0098, .0097, etc. That should buy a hundred years of generational gain claims.
There's always a smaller measure. And even when physics throws up a hard barrier, the fine hair that remains to max- er MIN- out the possibilities could be split into thousanths, ten thousandths, etc. The whole number will sound as familiar as whole numbers in nanometers now even if it is working within the fractional limits of only a single nanometer.
Besides, as others post often, even the current X nanometer process isn't literal. It's just a marketing "puffery" claim, apparently driven by the perceived need of a lower number in spite of the technology not actually representing the claim.
See "magical", "faster than 3090", 5Ge, "biggest network", "fastest network", 5G coverage map, "cool, ocean breeze" in coastal RE no matter how far you are from the coast, remarkable battery life claims, "lose weight without dieting or exercise", "lose 60 pounds in 6 weeks with this one small trick", 'elongation' pill/herbs/formula, how a swamp can become a natural preserve in RE puffery, "this miracle face cream will remove 20+ years of aging", wifi speed claims, broadband speed claims, SSD speed claims, Thunderbolt/USB speed claims, "this ship is unsinkable", diet candy, "It's easy... anyone can do it", "100% fruit- all natural", "I make $XXXXXX per month in only 1 hour per day and you can too", "Get rich quick with absolutely no selling", "The cure-all elixir", "Smoking cigarettes is good for you", "vaping is not as bad as smoking", "free range" <anything>, this bottled water is sourced from <exotic> place, kills 99.9% of germs, appearance of fast food in the ad vs. reality, "this one secret will make you rich beyond your wildest dreams", "valued at several times the price being sought today", "this time, it's different", any easy solution to make you thinner/more beautiful/younger looking, immediate ROI, "get in shape without setting foot in a gym", your personal data is completely secure in the cloud, favorable food label numbers until you check servings per container to realize that only a fraction of the single serving container is considered a serving, "everyone is obsessed with this <product>", "this one simple hack will do <wondrous things>", "free, unlimited fusion energy for all is only about 20-30 years away", just about anything politicians says that go against common sense or hard science, "turn $2K into $200K in only 2 months", etc. The full list could probably exceed all storage available for the MR website.