1) As you can clearly see on
https://blockchain.info/pools Bitcoin mining is condensed into mostly a few pools. Coinbase themselves own the largest % of Bitcoins after Satoshi.
What does mining have to do with anything? I agree that the hashpower isn't as well distributed as well as I would like it to be, but it shouldn't matter for as long as a single entity doesn't hold more than 50%.
2) Constant forks that are "accepted" undermine Bitcoin, such as Bitcoin Cash, etc. This shows to the average person that Bitcoin is more like play money than anything substantial. Do you see there being any variants of the USD? No, there's only one United States Fiat
No forks are actually accepted by the community as the
true Bitcoin though. Every fork is a side project and an altcoin. The moment it forks from Bitcoin, it becomes a different entity which takes advantage of Bitcoin's open source nature to use its branding. There is only one Bitcoin just like there is only one United States fiat. Bitcoin to Bitcoin Cash is far more comparable to, say, the United States Dollar to the Australian Dollar -- they may share a portion of their name but they're different entities.
3) Bitcoin could never be anything close to an ideal method of payment. There is absolutely no way to solve Bitcoin's volatility currently, hence it will never become widely adopted. Not to mention once Bitcoin's are stolen, the action cannot be reversed(Like it could with banks, etc), and in the future quantamn computing will break into Bitcoin. Those few among many are reasons the average person will never use this crypto to buy groceries at the supermarket. Also, bitcoin is becoming used less, as Steam and others have stopped accepting it due to it's extremely slow confirmation times and high fees.
I respect that opinion. It's easy to be pessimistic towards Bitcoin's future as a method of payment because of how things have been going recently. However, there is no guarantee that quantum computing can break into Bitcoin. The slow confirmation times and high fees are also set to be addressed by future changes like the Lightning Network. Only time will tell.