Nautilus or Aquanaut are considered just a few pieces of much larger collection of Patek Philippe connoisseurs
There are many other collectible models that are at very high prices and highly sort-after beyond that 2 sporty models.
They are even rarer and much harder to come by...only unnoticed by general public.
Some of them require recommendation from dealers along with buyers' portfolio of Patek watches and available only at a boutique.
Simply say, Patek (Switzerland) will decide if they want to sell or not to a buyer.
IMHO, rarity is one of key factors of collecting.
If one can buy a model (even with premium) from either dealers or gray sellers, that model is not truly rare krab.