You are only watching the last leg, until it becomes unprofitable to mine at any electricity price.
If that becomes the case, then bitcoin's future existence is at risk. Even once the block reward is zero, we still need miners to be operating and sustained by transaction fees, or else the hashrate falls to zero, no new blocks are found, and therefore transactions aren't possible. Of course, that would never happen because the difficulty would readjust and so it would again become profitable to mine with less powerful hardware using less electricity.
I also think that Mining for Bitcoin will not last long it has an end after the last block had been mine all mining procedures will also come to a halt
There is no "last block", or at least if there is, it's because bitcoin is no more.
Last block no, last coin yes.
You say (now) its at risk, but this has always been Bitcoin's design. Take a look at some of the altcoins that people don't care mining anymore, then you can have an educated guess to what will happen.
Fact is Bitcoin miners will greatly diminish, but not disappear. It might go back to what it used to be in the first few years, this time only people that want to do it out of their own pocket. If you think (now) that this is a mistake, you never learned Bitcoin's design.
Since the beginning, Bitcoin (network) doesn't care if 10 or a million miners exist. The blockchain is still safe, and the nodes work and ensure things for everyone. And yes, expect the number of nodes to be higher than the number of miners, when it becomes completely unprofitable to mine in the future.
If you have free electricity, for example because you invested in renewable generation, it would be technically profitable, or perhaps if there is some market for the so called "virgin" coins, which are rapidly diminishing in production.
After 10 years you never saw this coming? What have you been doing? This is NOT a problem, it is doing as intended. Less miners do NOT put Bitcoin at risk, and there is never going to be a complete stop in mining, there is always enthusiasts that don't care.
Now you might remember Cannan's idea of putting asic miners inside household appliances, this is probably something that will be revisited. Canaan simply acted a bit too soon, but Asic miners inside TVs, Wifi routers or even simple heat spreaders will cater to these people, that will want to keep Bitcoin's network running, or the merchants that have already embrace it and are running nodes too.
The hashrate will reduce, but not as much as you think. Because the more efficient asics compensate the situation. However, later it won't be that profitable to manufacture those asics, and much less devote so much money in r&d to improve them as much as with the market in 2016. Even Bitmain will have to reconsider their core business if they want to remain around.
This could take the next halving or two, but it is coming, like it or not. The theory is that at the end Bitcoin transaction fee provide the incentive, i guess so but LN threatens those fees to be negligible anyway so it will be mostly enthusiasts many in from this forum (i expect the large Chinese, etc. miners to leave).