Other:
The fixed blocksize limit in Bitcoin.I have been involved with Bitcoin since 2011. Yes I have read Satoshi's paper
https://bitcoin.org/bitcoin.pdf and believe in the vision for Bitcoin as presented in the introduction:
1. Introduction
Commerce on the Internet has come to rely almost exclusively on financial institutions serving as trusted third parties to process electronic payments. While the system works well enough for most transactions, it still suffers from the inherent weaknesses of the trust based model. Completely non-reversible transactions are not really possible, since financial institutions cannot avoid mediating disputes. The cost of mediation increases transaction costs, limiting the minimum practical transaction size and cutting off the possibility for small casual transactions, and there is a broader cost in the loss of ability to make non-reversible payments for non-reversible services. With the possibility of reversal, the need for trust spreads. Merchants must be wary of their customers, hassling them for more information than they would otherwise need.
A certain percentage of fraud is accepted as unavoidable. These costs and payment uncertainties can be avoided in person by using physical currency, but no mechanism exists to make payments over a communications channel without a trusted party. What is needed is an electronic payment system based on cryptographic proof instead of trust, allowing any two willing parties to transact directly with each other without the need for a trusted third party. Transactions that are computationally impractical to reverse would protect sellers from fraud, and routine escrow mechanisms could easily be implemented to protect buyers. In this paper, we propose a solution to the double-spending problem using a peer-to-peer distributed timestamp server to generate computational proof of the chronological order of transactions. The system is secure as long as honest nodes collectively control more CPU power than any cooperating group of attacker nodes.
I have quoted this before. The critical part is in bold. The reality is that Bitcoin cannot meet the stated vision and objective with a fixed protocol limit of approximately three transactions per second on the blockchain. I came upon Monero in 2014 on this thread
https://bitcointalksearch.org/topic/rpietila-altcoin-observer-624223 while researching the blocksize issue in Bitcoin. At that point my total involvement with alt-coins was Namecoin which I had obtained as a by product of mining Bitcoin, and subsequently successfully traded for Bitcoin during the Bitcoin bull market of 2013. I had enough respect for Risto as a member of this community for me to at least do some due diligence on Monero even though there was no mention of the blocksize issue as a reason to buy Monero in the post. After discovering that Monero has at least the a reasonable chance of a viable solution to the blocksize issue in Bitcoin the rest became history. Many if not most of the supporters and detractors of Monero consider Monero primarially a fungibility, anonymity, privacy coin. My take is that Monero first addresses a much more fundamental issue; namely the ability to be able to transact in the first place. After all there is little point is having concerns over fungibility, anonymity and privacy of one's transactions if one is not even able to transact to begin with.
Edit 1: By far the majority of POW coins have the same fixed blocksize issue as Bitcoin with in some cases the ball being kicked down the road. Notable examples are: Litecoin, and "Monero competitors" such as Dash and ZCash.
Edit 2: I have come to the conclusion that for a Monero style adaptive blocksize to work a trail or permanent emission is an absolute must. Given that this involves for most POW coins a radical change in the social covenant I do not see a simple solution for most POW coins including Bitcon here. One notable exception is Dogecoin since it already has a tail emission.