Ever since strict regulations were introduced in 2017, we've seen a substantial decline in Bitcoin's price across the market. It's believed that 2017 was the year where Bitcoin and other cryptocurrencies went "mainstream" as many people adopted them for their own benefit. The introduction of new regulations, ETFs, futures trading, and Bitcoin forks (BCH, BSV, etc.) could've had an impact over Bitcoin's price. Whales could be manipulating Bitcoin's price as we know, preventing the pioneer cryptocurrency for reaching new All-time-highs in price.
Imagine if every Bitcoin halving, prices would remain the same or lower than they were before. This would turn out to be completely unsustainable for miners, resulting in decreased security of the Bitcoin blockchain. Of course, the way Bitcoin was designed tells us that price should be going up over time. But I've seen how regulations and events in the mainstream world have negatively impacted Bitcoin's price to a point where it has taken a very long time to rise back up to its original levels. It's been almost 2 years since a bear market occurred (2018), and could last longer as we know it.
As it's said, "Patience is a virtue". We as "hodlers" of Bitcoin should be patient in order to see better results in the future. But, what if Bitcoin never reaches a new ATH? Then, I'm afraid that most people "hodling" Bitcoin will lose all of their investment in the long run.
What are your thoughts?
That situation might simply delay the day when the limit will be breached, but i'm sure that day will come. Sooner or later Bitcoin will reach 20k. If it gets more stable, as you say, it might simply take more time, years or decades, doesn't matter. But i'm quite sure it won't lose its value permanently.
I actually expect that, the price will remain the same after halving just like you say, if there is a price change it will be before halving, and then a correction depending. You are quite incorrect about security, Bitcoin is secure with almost any hashrate, and this hashrate isn't going to change too abruptly, the network will almost certainly have enough time to adapt gradually to any new situation.
You even want to make it look like its some sort of danger, when its actually what its going to happen, and has been happening all these years. Mining is less and less profitable, therefore there will be less miners, but no, it won't make Bitcoin less secure.
What you don't get is that if miners leave its because it has become too expensive to mine, and so any "attacks" would be as well, they go together. This is why the security of the network is quite stable regardless. Of course you could argue the network is a tiny bit more secure with many more miners, but the opposite isn't quite so.
Mining aside, the value of Bitcoin remains since the vast majority comes from already minted coins in the market. Time has only reduced the amount of coins that come from mining, and has becoming almost negligible. Most of the coins that will ever be are already out there, and the current price is from this supply while the demand tends to increase (pushing the price up). The mining slows this somewhat but its destined to reduce until it disappears.
In any case don't expect the ath to be breached anytime soon, but even less expect losing value, it won't, not in long term anyway. There is no reason to ever leave Bitcoin except when you actually want to spend in something. Leaving out of fear that might lose its value, will only lead you to net loss. You WILL repent later. Just hold, and if it goes down, hold tighter (and buy cheap while you can).
There should not be a reason to find a time to sell, for selling sake. Bitcoin should be viewed as something you get in but not get out in the long run, just use what you must and hold on to the rest.
If you want to play short term trader, that's another subject entirely. As a holder, you shouldn't even think of selling, ever.