First, Bitcoin will have to hit the capacity limits of what is possible today. It has not, and even with no technical advancements there is a lot of room for scaling. Especially if you add on chain scaling solutions such as Xtreme Thin Blocks (developed by Bitcoin Unlimited
, and portable to all 'competing' client implementations).
Once it has hit the current technical limitations - then you need to look at Moore's law, as the limits of what is possible keep getting pushed back.
I just bought a 6 TB harddisk, for just over $100 I think. That was unthinkable 5 or 10 years ago.
Before that, I bought a $35 raspberry pi 2 with a $35 128 GB micro SD card. It is running a FULL, unpruned, bitcoin classic node. That was unthinkable 5 or 10 years ago.
So you are right, that bitcoin's growth must exceed the current hardware limitations AND Moore's Law for there to be a problem. Those problems could potentially be fixed with LN, Side Chains, etc. They would work then, because there would be sufficient on chain capacity for them to do what they need to do, without ridiculous requirements such as "prepay your LN account with 6 MONTHS of expenses" (seriously!)
Be part of the solution! Let's scale