Bitcoin is facing a problem because its designer didn't know how to solve this problem, and in fact, the very first discussion points with Satoshi were exactly about this: in a system where every user is supposed to be aware of every transaction of every other user (which was the basic core idea of bitcoin), if this system grows, how are you going to cope with the extra demand on network resources, computing resources and storage resources *for every user* ?

This is the famous "block chain scaling problem".  However, is it really a problem, and is the resource problem the core of the problem ?

The answer to both is "no".  There is no actual resource problem in scaling, and it is not the true problem at all.  There ARE other problems, related to this, though, but the resource problem is a false problem.

Why ?

First of all, because the scaling is not infinite.  There is a finite amount of potential users of bitcoin.   Even if this finite amount is big, and is reached, the resource problem is not RIDICULOUSLY large.  Satoshi pointed out in 2008, that one can expect, IF EVER BITCOIN IS GOING TO BE A WORLD CURRENCY, to have about 1 GB blocks.

1 GB blocks, even though large, is not ridiculously large.  1 GB every 10 minutes, is of the order of 150 GB a day, or ~1 TB a week.  While this is a lot for an average user, this is not ridiculously large, and by the time IF EVER, bitcoin is going to become a world currency, this technical problem will not be significant.

Most probably, bitcoin will NOT become a world currency, simply because it has been designed as a speculative gambling token, and NOT as an ideal currency.  So we are considering most probably a problem in a case that will not happen ; and if it happens, but sufficiently far in the future (say, 15 years from now), it won't even be a technical problem.

In other words, we are right now thinking about something that is a technical non-problem, for an improbable situation (namely, where bitcoin were going to be a world currency, while it is ill-designed for that purpose in any case).

The second answer Satoshi provided, which is very true, is that NOT EVERY USER NEEDS A FULL COPY OF THE BLOCK CHAIN.   There is no use for that.  If there are A FEW servers of the same block chain around, every user only needs a VERY TINY PART of that block chain, namely, what a light wallet uses: the SPV protocol.

The whole argument for the need for decentralization to have all Joe's using bitcoin to have a copy of the whole chain in their basement, is bogus, because the only DECIDERS on the block chain are the miners.  Joe's server in his basement serves no decentralization purpose.  Joe has nothing to say, even if he copies all the Petabytes of the hypothetical mega block chain.

So:

1) most probably bitcoin will not NEED TO SCALE to full currency usage scale, because bitcoin is ill defined as a currency (it is a speculative token for speculators, not a currency for buying coffee - it is not ideal money).

2) even if it were to scale, which is improbable, if it does it in the sufficient future (say, 15 years), the technical burden is not gigantic for users that want to copy the block chain.

3) users don't even need to copy the block chain.  Only a few servers doing so is enough for SPV wallets to function correctly.  There's no power to be had by having a copy of the unique block chain over which one has, in any case, nothing to say if one is not a miner.

==> the whole discussion about decentralization and resources and so on is a FALSE PROBLEM.

But what is the REAL PROBLEM ?

The real problem is the remuneration of the miners when the block reward runs out, and the game-theoretical aspects that follow from that.  Without a block size limit that creates artificial transaction scarcity, miners cannot force users to compete for a scarce resource, and will not get paid enough to secure the block chain with the silly PoW security.  Moreover, without fees, the block chain room becomes a resource that will be wasted by spam or many parasitic applications.

The problem that Satoshi didn't know how to solve and which has no good game-theoretical solution in the frame of the (silly) economic rules that Satoshi gave to bitcoin, is: how to secure the chain when the block reward runs out ?  THIS is the real problem.  Nobody knows how to solve it in a satisfactory way with PoW and sound money theory.

This is what will kill bitcoin in the end.  Not the mumbo jumbo about resources or decentralisation.  These are straw man arguments to keep people away from the true problem.