Thank you,
but, about this, when it takes 3 hours to compute for
1Bitcoi prefix, 3 hours is sufficient to generate billions addresses if you see what I mean

Well yes, but a billion adresses still is absolutely nothing.
See Danny Hamiltons answer to put things in perspective.
2^30 (≈≈a billion) vs 2^160 (all the adresses in existence, well- let's just assume that for simplicity) - the difference is unimaginable.
But, most pools use ASICS only which perform SHA-256 only- so- (someone correct me if i'm wrong here.)- it would be wrong to compare the "computing"/hash power of a pool to generating addresses.
You are correct.
The ASICs used by mining pools are not capable of generating bitcoin addresses.
However, lets use our imagination and create a world where some very wealthy person decides to invest all of their wealth into creating special ASICs that are capable of generating Bitcoin addresses.
Lets imagine that they are able to generate addresses at the same rate that the current bitcoin network is capable of generating hashes. In other words, lets imagine that they can generate 115,000,000,000,000,000,000 addresses per second.
There are 2
160 different bitcoin addresses of the type that start with a 1 (legacy, P2PKH).
(2
160 addresses) / (115 X 10
18 addresses per second) = 1.27 X 10
28 seconds.
So, it would take about 1,270,000,000,000,000,000,000,000,000,000 seconds to generate all possible addresses (assuming you never generated the same address twice).
Replace 115*10^18 by 2^30 ( ≈a billion p second ), and you can perhaps put things into perspective a bit better.