To answer the question of what will happen to Bitcoin in the future, a distinction must be made.
It is not necessarily a foregone conclusion that Bitcoin‘s technology will evolve in the same way that the asset’s deployment in the financial markets is evolving.
Bitcoin’s technology evolves very slowly. It is enough to consider that in the last four years there has been only one update to its protocol, and in the previous four there was again only one.
In fact, in terms of technology, very little may actually happen to the Bitcoin protocol in the future: most of the evolutions will most likely take place on the second layer Lightning Network, rather than on the underlying technology of the Bitcoin protocol.
So from the perspective of the protocol, no real and significant changes are expected in the future, from any point of view, not even from the wacky hypothesis of replacing PoW with PoS.
A different discussion might be about, for example, energy consumption and network security.
Regarding energy consumption, which is currently very high, in the long term it is possible that it will go down. In fact, energy consumption depends largely on miner revenue, and this is halved every 4 years or so.
Since the revenue is in BTC, if in the meantime its value doubles, the value of the revenue would actually continue to increase, but it is possible that sooner or later the value of BTC will stop increasing very much each cycle. So sooner or later the time will come when miners will be forced to reduce consumption because of the inevitable reduction in revenue.
On the other hand, as far as network security is concerned, it is extremely difficult to make predictions, because barring unforeseen events, nothing different should happen than what has already happened. In the long term, only quantum computers can pose some challenges, but on such a long timescale that there will be plenty of time to find solutions (some of which already exist).
The discussion becomes much more complicated if, on the other hand, we focus on the long-term evolution of the BTC asset.
Bitcoin’s vision in the long term
The first point to address is definitely regulation, because much of what will happen to Bitcoin in the future depends on the eventual laws that states will release regarding it.
For now, it seems that the direction is towards a relatively permissive regulation, globally, with a few rare exceptions including China.
However, it seems that regulators are blunt-armed, so much so that China itself is not really succeeding in blocking the use of cryptocurrencies. So even with restrictive regulations, there is always a real possibility that people will find ways around them, or even ignore them.
In this sense, it is absolutely impossible to make long-term predictions, not least because the generally permissive sentiment could also change from one moment to the next.
The second point, which is actually more important than the first but depends closely on it, is mass adoption.
Although there are already two countries in the world that have adopted Bitcoin as a legal tender (El Salvador and Central African Republic), and despite the likelihood that other countries will make a similar choice in the future, the use of BTC as a means of payment is struggling to take off.
At present it seems more likely that BTC will not be commonly used for payments in place of common fiat currencies due primarily to its volatility. However, it is possible, though not at all certain, that sooner or later this volatility will be reduced enough to make it usable as a means of payment as well.
Beyond that, it might have a much better chance of spreading as a tool for balancing the central banks’ expansionary monetary policies, even if that means a concentrated spread in the financial markets and the preserve primarily of those with large amounts of capital.
From this point of view, however, much will depend precisely on the monetary policies of central banks, which, however, are unlikely not to become expansionary again sooner or later.
The final consideration on BTC
One final point remains to be addressed, the one generally considered to be of most interest: price.
While it is virtually impossible to make real predictions about the price trend over the long term, it is worth mentioning that in case of very significant changes, these will certainly have a huge impact on all other aspects.
On the other hand, BTC is primarily just a financial asset, as well as an innovative technology, and therefore its market value is a fundamental and very important feature of it.
Although there are several detractors of Bitcoin who claim that its price could even go to zero in the long run, most experts seem to be convinced that it could rise. There is no certainty about this, and the hypothesis that it could lose value again is probably as likely as the opposite.
But in the event that central banks, and especially the Fed, resume flooding the markets with money created out of thin air, it is hard to believe that the price of Bitcoin could fall. Just as it is hard to imagine that they will not return to it sooner or later.