Oh I get it! You're a bubble-boy!
And you're an insulting pretend-to-know-it-all.
You never actually saw fog in real life. You imagine it as some sort of thin layer of smoke.
No, it isn't smoke, and I've never said that it was. It's condensed water. And the thickness of fog, in both density and actual thickness of the layer, depends on the conditions. I've seen ground fog where you can look up and see the sun but can't see the person ten feet away. If you've never seen that, then you are not one to lecture anyone on what fog looks like.
And I know that you can, indeed, fly out of the fog, because all fog really is is a cloud that's touching the ground. You probably have seen that clouds can be very regional in nature, haven't you? If not, again, don't lecture your betters about it. Yes, I've actually done that, too. I've departed an airport when I can see up but not laterally because I know as soon as I'm airborne I'll break out into the clear.
I've also taken off from an airport where it is severe clear, but there are pockets of ground fog (about 100 feet or less thick) in all the surrounding low areas. It's really very pretty. It's worth the price of admission.
If all you think fog can be is the dense, can't see your nose stuff, then you're ignorant. And if you think the dense, can't see your nose stuff has to cover more than a few hundred square feet, you're ignorant.
Pilots never get to see the ground if there is fog.
You truly know nothing about the subject. It is very common, especially in ground fog, for pilots to be able to see the ground but not far enough to see the runway a mile away. That's because the fog layer is vertically thin. I've done it more than once. Personally. In an airplane. Even in thicker layers, when the visibility is 1/2 mile, you can't see the runway a mile away but you can easily see the ground that's only 400 feet below you. Been there, done that. I guess it's not a very restrictive bubble I'm in. Your claim that pilots "never get to see the ground" is just ignorance at best.
And that ability to see the ground when the runway or the runway environment cannot be seen has led people a lot smarter than you to their deaths. They'll be on an approach, see the ground, think they know where they are, and think they can keep descending because the runway is "right ahead of them". Except it isn't and they run into a building or a power line or an antenna or .... So you are just flat out wrong when you say that pilots never get to see the ground if there is fog. Pathetically, miserably, horribly wrong.
And then, if they see the approach lights, they can get down to 100 feet AGL but NO LOWER, unless they can see something of the runway (the rules are here. At that point, they have to SEE the runway. Visible. As is true for many of the rules, this rule is there because there were too many people doing what I talked about in the previous paragraph. "Just a little lower ... WHAM!"
If the visibility is at 10 meters,
Not every occurrence of fog is that dense. And even if it is that dense right here, a mile away it can be clear. And most pilots won't be on an approach when the visibility is only 30 feet. That's rounded down to 0 anyway.
Meaning that they need AT LEAST 100 meters of visibility in order to see the ground 1 second before touchdown.
It's ALL on instruments.
The closest ILS has a minimum reported visibility of 1/2 mile before a commercial operation can even TRY to make the approach. If the visibility is just 300 feet, he can't start. Private pilots can make all the attempts they want, but if they get to DH (200 feet AGL) and can't see the runway environment, they can't go any lower. Guess what that means? The landing is done VISUALLY. The instruments get the pilot to the place where he can see the runway to land, that's it. So no, is it NOT ALL ON INSTRUMENTS. That's just ignorance on your part, converted to arrogance by your attitude.
And those minima I mentioned are for standard ILS approaches. Many airports don't have ILS approaches. They're stuck with VOR or other non-precision ones. The minima for those approaches are even higher. For a 747 (category D), the minimum reported ground visibility at the same airport is one mile. Your 747 going into an airport with or without an ILS will never be making an approach if the visibility is 100m. (Except for the few CAT III airports.)
What IS really fun is that private pilots CAN attempt an approach when the ground visibility is reported as 0 because they are not prohibited from trying, and they might even be legal to land because the visibility they need is flight, not ground, visibility. Of course, if you land at an airport that has a reported visibility less than the approach minimum then you may have to explain how you came up with a better flight visibility, but the FAA wasn't in the plane with you and they can't tell. I've made approaches to airports that were 0/0 and the commercial guys were in holding patterns because they couldn't even start an approach. It's fun. Some people bungee jump. I shoot 0/0 approaches.
Same goes for rain or snow. 100 meters of visibility - 1 second of space in front of them.
There is no "1 second" rule. And your 100m == 1 second puts the aircraft at 194 knots. That's faster than landing speed. That's more than twice what a single engine GA aircraft will be going. You really don't know what you're talking about. Please stop.