Their point is that the current decentralised Bitcoin is functionally unusable and simply not ready for mass use.
In that sense, a truly decentralized Bitcoin that people can actually make use of doesn't exist.
That is definitely not true. As mentioned there is local bitcoins, atms, meetups, bisq, just to name a few options, were you can exchange bitcoin for fiat. The options are there, are used and are even mature.
Centralized exchanges provide a lot more essential facility than fiat to bitcoin conversion. In particular, they provide acceptable transaction fees and acceptably fast transaction turnaround time.
Unless you use an exchange. The best way to handle payments would be direct transfer from one personal wallet to another. No exchange necessary. No red tape. Buying the Bitcoin with fiat so you can put it in your own wallet for direct transfers is the problem. You generally need a centralized exchange for that. Also, the person you transfer btc to will generally need a centralized exchange so they can convert to fiat and actually use the btc. The whole ecosystem is a mess for people who just want to use it as a way to transfer funds.
Hm, there is https://localbitcoins.com/ or https://coinatmradar.com/. It is way cheaper than moneygram or similar services, just check out the options... from where to where do you want to transfer? You would even find people on meetups which would help.
Interesting. I didn't realize Bitcoin atms were so prevalent.