Why didn't the creator didn't manage to allow people to be able to mine without needing a mining pool ?
I think, that was exactly Satoshi's intention.
But nowadays, it would be hard for you to mine 1 block because you don't have much mining power if you are alone.
So the people decide between
Do I want x$ per day (irrelevant wheather I mine a block) or
Do I want 25*15,000$ + fees (if I mine a block what happens maybe 0-1 times) Most people want(ed) the permanent money.
And that's the reason why there are only a few big mining pools instead of millions of separate miners.
Bitcoin was and still can be mined by an individual that is not part of a mining pool. In fact, the network does not actually know about mining pools nor does it care about them. In the beginning, Bitcoin was mined by individuals using their own CPUs. Then, as more and more people wanted to mine Bitcoin, miners began using faster and faster hardware, moving from CPUs to GPUs, and then to FPGAs, and now to ASICs.
Unfortunately the rapid growth of mining meant that it was harder for an individual to be able to find a block. So people began pooling their resources together. A bunch of individuals would mine as a group and the block reward would be split up among themselves. That group would have a higher chance of finding a block than just one person mining by himself, and while each would be paid less, they would be able to earn Bitcoin more consistently as they have a higher hashrate than just one person. And thus mining pools were born.
So it isn't that Bitcoin was designed to be mined at mining pools, but rather that mining pools were a natural evolution from the increased overall hashrate of the network.
If you don’t want to invest in the blockchain technology and looking for any third party who help to mine your favorite cryptocoin. Than the Mining pool is the best option for you.
In Bitcoin mining or any other digital currency mining, hardware plays a very important role. Initially, CPU was the only hardware device which miners used to mine bitcoins. The total mining depends on the hardware that is to be used for mining. Here, Mining does not need any special hardware other than GPU. A GPU is the Graphic Processing Unit that allows the miner to mine cryptocurrency with a good hash rate. The hash rate totally depends on the hardware that is to be used for the mining of cryptocoins.
Also the ASIC chip is specially designed to perform mining activities. An ASIC model cannot be remodeled to perform other duties.
There are many advantages of joining the mining pools. For now, i will just only focus on increasing the overall hash rate percentage. We all know that if the probability of success is p then prob. of failure is (1-p). Lets assume a miner controls fraction "p" of overall mining power and has prob. p to mine the new block then (1-p) prob. of not mining the new block.
I hope you know about bernaulli's distribution in probability so according to that variance = p*(1-p).
so How many blocks are mined in a year ?
every 10 min = 1 blocks
one hour = 6 blocks
one day = 24*6 blocks
one year = 365*24*6 blocks
we find that the miner who has prob. p of mining the new block is expected to mine 365*24*6*p blocks per year.
then variance = 365*24*6*p*(1-p).
Now we will calculate the standard deviation (in blockchain, it is the deviation that how much this miner's reward is going to be deviated from the expected reward). I hope you know about the reward system for miners.
standard Dev. = [sqrt]Variance / expected return
variance = 365*24*6*p*(1-p)
expected return = 365*24*6*p
so std. dev = [sqrt]365*24*6*p*(1-p) / 365*24*6*p
now suppose a miner owns 0.01% of hash rate in network i.e prob. p=0.0001
std. dev = 0.4364 or 43.64 % deviation for hash rate 0.01%. (by putting the value in the above formula)
The solution to decrease this deviation and variance is to join mining pools and work together to increase the overall hash rate percentage, which is exactly working now a days.