most people see messaging apps like Signal, WhatsApp and other third party apps for personal use only.

In Europe, businesses, especially small businesses often use WhatsApp, to the point of putting its logo next to their phone number on signs. I wonder what creates the perception where you are that messaging apps are for personal use, not business.

Signal, being owned by a nonprofit has a bit more resistance to that than most.

That's the main reason I recommend it over alternatives with similar technical capabilities, such as WhatsApp.

I'm not surprised they could. I've worked on things that send SMS messages and I'm aware that carriers filter for spam and scams (perhaps not as effectively as one might hope).

I'm surprised to hear of messages being blocked for mere profanity.

Anyway, SMS sucks, default to something else and fall back to SMS as a last resort. Gently encourage your contacts to use Signal.

SMS fallback. A feature which you can use with any app on Android

SMS fallback is not a common feature of internet-based messaging apps on Android. Signal used to do it, but does not now. I don't think WhatsApp or Telegram ever did.

I have no doubt about the part where iPhone fans waste no opportunity to tell someone else they should get an iPhone. It's the other side of the argument that falls flat: Alice receives video from Charlie that's perfectly fine, but Bob's iPhone sends a pixelated mess, and Bob says the iPhone is better?

Interest in RCS is recent - newer than iMessage, which launched in 2011. RCS with Google's proprietary extensions is just another proprietary messaging app, and I am not particularly excited about it.

even so far as “patch” a fix that was created to make it possible for their customers to communicate securely with Android users.

There's no shortage of options for doing that. What Apple wants is tight control over all of its walled gardens, which should be no surprise given the company's history. They're very good at making it appear as if decisions made to increase their profits are aligned with the interests of users. It's probably even true that someone would have exploited the technique Beeper Mini was using to send spam if Apple hadn't closed it.

Just doesn't seem plausible to me. If Alice gets low-quality images from Bob and higher-quality images from Charlie, her most likely assumption if she's not sophisticated enough to be aware of the cause is that Bob's phone has a bad camera.

It seems unlikely to have that effect when the recipient presumably communicates with people who have other brands of phone, from whom they receive better looking media.

It seems like an odd decision to me, as it would make the iPhone look like it has a substandard camera to someone receiving media from one by MMS.

MMS does have size limits that can hurt image quality, but I have the impression iOS applies limits of its own that are considerably lower. I'm not sure why anybody in 2024 wouldn't have at least a couple modern messaging apps, but it seems a lot of people don't.

Android doesn’t support iMessage

I think it's the inverse: iMessage doesn't support Android.

Those aren't equivalent statements; the first implies that something about Android makes it impossible for Apple to produce an iMessage client for it when that is purely a business decision on Apple's part.

Major privacy issues that come to mind include:

• App store lock-in on iOS combined with terms incompatible with the GPL mean that some of the most privacy-respecting software cannot be distributed for Apple's mobile devices.
• Apple proposed, but ultimately did not implement client-side scanning for end-to-end encrypted cloud storage. That such a thing even made it to the public proposal stage shows either incompetence (unlikely) or a lack of serious commitment to privacy (more likely). Apple's proposal may have emboldened EU regulators who are trying to mandate client-side scanning for encrypted chat apps.
• Browser engine lock-in on iOS means hardened third-party browsers are unavailable.
• The popularity of Apple's platform-exclusive iMessage service in the USA may be hindering adoption of cross-platform encrypted messaging. On the other hand, without it perhaps most of its current users would use SMS, which is obviously worse.