For those of us lucky enough to sail newish boats, maybe the mutli hull owners who claim to stay level at all times and for those who never really venture to sea or have never sailed in really tough conditions, non-marinised stuff is probably OK.
My boats because of my budgets have always been older with imperfect deck seals and hatches that leak ever so slightly when green waves pass over the deck. The result is that all the gear down below is subjected to salt in way bigger concentrations than a boat that languishes for the most part in a marina.
I have had my cockpit filled to the brim with waves several times and 20 gallons of salt water leaks in past the joints and gaps in the wash boards. It either ends up in the galley or on the chart table. I shudder to think what my stove and radios would look like now if they came from Walmart.
I have thrown away huge amounts of stuff that we bought on the cheap rather than pay the apparently extortionate prices asked for "marine grade" stuff. And still, there are many items that we use at sea even though the life is dramatically reduced but then it's about economies of scale. A bicycle for example in stainless is prohibitive, the supermarket model will last 2 years then it gets chucked and another one is bought for next to nothing.
I find it interesting that some of the folks above who decry marinised products are the same ones who earlier vehemently insisted that they will only ever use tinned wire and crimped joints and all that other stuff. You don't have tinned wire in your car or your home.
I can't imagine going to sea with a Coleman stove in place of my Force 10. And I reckon we won't see to many of the above boat owners fitting mild steel barbeques on the back rail
Don't misunderstand me, I get really ratty as well when I get stung with huge prices but there are some marinised products that are not negotiable.