First of all - every transaction on a blockchain is recorded on that blockchain. It may be difficult to determine who is who or even the specific amounts of currency being transferred, but it's not impossible.
Well yes every transaction is included in the blockchain. But with projects like Monero, knowledge of these transactions does not allow you to discover the identities of the participants.
And the difficulty, while strictly not technically impossible, is so improbable that we have a greater likelihood of the sun supernovaing tomorrow than you being de-anonymized.
Yes, but as I mentioned in the post, your anonymity depends on where/how you're spending the currency. If you're ordering from Amazon, there isn't much anonymity if you actually want your purchase delivered. There are ways to get around that - like shipping to some place where you don't actually live - but the question is whether most people will go through the trouble of doing that.
Peer-to-peer on the blockchain is pretty much anonymous. Actually purchasing things from businesses in the real world opens various doors to your personal information. In a world with increasing online shopping/interaction, the trend is not to revert to in-person buying/selling any time soon.
Monero may be pretty much anonymous/private, but how many people want/need that and are willing to take all of the necessary steps to use it as their primary or even secondary currency? And if purchasing anonymously or in-person is preferred, why wouldn't they just use cash, which is much simpler to acquire and spend?
I agree with the point you make in your post. You are right, interacting with most business is destructive to your anonymity.
I think that there will be decenteralized marketplaces that are able to keep the anonymity. There is something that can solve the problems you mention.
The anonymous products will improve their usability, it will take time.
The difference between Monero or Zcash and Bitcoin is that it's trivial to link one address to another in Bitcoin. All the information is laid out before you. Monero and Zcash break that link. So even though you could be shown to be spending them if someone dug deep enough, it's harder to show where that privacy token came from. Its chain of custody, who had what and when, is either really fuzzy or opaque. This is much greater privacy than what's offered by a blockchain like Bitcoin.
Man I get the creeps when I read things like ... if you actually want your purchase delivered ... like shipping to some place where you don't actually live ... .
It all sounds troubling. Anything else comparable in the history of currencies to which can be compatible to the on set of bitcoin?