^ Here's a chart that shows the historical blocksize growth along with the limits, the "block fullness," and some commentary on how the limits have changed in the past and may change in the future.
Credit to Solex for the 1MBCON Advisory System Status and DeathAndTaxes for digging up the GitHub commits that introduced the blocksize limits.
Wow! Very informative graphic, Peter. This needs to be seen more widely.
20/20 hindsight is always easy, and we can see that three things went wrong.
Satoshi implemented the limit back-to-front i.e. it should have required consensus to renew it, not remove it:
If block-height < 123,456
max-block-size = 1MB
He disappeared before he could use his authority to modify the change.
He did not expect it to become a sacred cow:
C'mon that's totally unfair to the majority of developers (again). It is not simply a 'sacred cow' and that totally over-simplifies the problem while casting negative aspersions against most of the developers.
These guys have worked themselves to the point of mental exhaustion in some cases to keep this thing scaling up to handle the transaction growth rate thus far and have made huge advances. They would all simply agree (ya know, a consensus) to raise the limit if it was such an obvious 'fix', it is not and there are no obvious fixes, that is just wishful thinking by the unthinking majority. Raising the limit is the last ditch 'suck it and see' hail mary pass when everything else has been optimised as much as possible ...
If the limit gets raised substantially above the technological improvements growth rate I'll be pulling the vast majority of my investment out because it is not going to be operating like we thought it would, i.e. it won't be a clearing and settlement digital gold network but a paypal2.0, fun internet googlesque reversable, traceable payments network