modal verbs - I have two questions about how to use 'will'

There are two sentences that I'd like to fully understand.

Only 30 years ago, it was almost impossible to come across a family that had a car, but Korea has changed beyond all recognition and cars have become very common. More often than not, one family 'will' have 2 or 3 cars.

I can't understand why 'will' is used. What if I use just 'has' instead of 'will have'? All I know about how to use 'will' is 'voluntarily action' or 'prediction'. Could you help me understand the difference 'will' and 'will have' above sentence?

Once I'm done with my banking, everyone wishes me a good day and someone 'will' always be on hand to hold the door open when I leave.

Similarly, I'd also like to know the difference 'someone is always on hand' and 'someone will always be on hand'. For me, it is much easier way that I use the former than the latter.

Thanks in advance.

Answer

"Will/would" is originally a verb that expresses volition, but this use today is limited. It is mostly found in negative sentences such as "I won't have it" meaning I don't want to tolerate it.

Today "will/would" is mostly used as auxiliary verb for future tense and conditional.

But there is a third use of "will" for describing behaviour or qualities that are normal and always found to be true as in

1 Paper will burn (if you set it on fire).

2 Wood will float on water.

3 If the temperature is below zero rain will fall as snow.

Here "will" has nothing to do with volition or future tense. Grammars speak of "habitual actions" or paraphrase by saying "used for things that always happen". This is a special use of "will" that is not so easy to explain.

By the way, "will" can be a full verb (will/willed/willed), expressing volition, but it is relatively rare. Etymonline translates Arabic inshallah as "If Allah wills (it)."

Added: The Longman English Grammar by L.G. Alexander has will/would for habits in paragraph 11.63 "will/would" to describe characteristic habit/behaviour

1 In fine weather, he will often sit in the sun for hours.

2 As he grew older, he would often talk about his war experiences.

3 Boys will be boys. (Common fixed phrase)

4 Accidents will happen. (Common fixed phrase)

(Added: Thinking about this use of will/would for characteristic habit/behaviour I would say this is an extension of the future tense: It will be so always or mostly.)

And in paragraph 11.64 "Will" and "would" to describe natural tendancy

5 Water will boil at 100°C.

(Added: characteristic behaviour of things: I think this is the same extension: It will be so whenever you check.)