This was a great article! It provides a lot of past details that most people wouldn't know about, especially about Pavel Durov (who is an eccentric character, as seen in the posts on his channel).
I'd actually pay a monthly subscription for the value Telegram has given over the years. The pace of development is unmatched by any other platform. I know Telegram chats are not end-to-end encrypted by default. Pavel Durov has explained, and I'm sure it's somewhere on Telegram's site too, that a big reason for not doing E2EE is enabling fast search (on the server). And it shows: Telegram has the best search among chat platforms and is even better than search on social network platforms with more features like Facebook. Maybe they have ulterior motives and/or aren't technically able to provide E2EE for all chats. So far, it hasn't had widespread scandals (other than TON) like Facebook/Meta has had.
This is not to claim that Telegram doesn't have design flaws or drawbacks. But no other platform can catch up to its UX and features for at least a few more years, and that gap seems to be widening as time passes. If any platform were capable of doing so, it would've happened already.
Among Telegram's many features (if you use Telegram, check how many of these you know about):
* Phone number hidden from others? Check.
* Username that can be given to anyone or published anywhere for others to contact? Check.
* Multiple accounts on one app? Check. (the official Telegram clients allow up to three accounts)
* Fast and reliable (comparatively) message delivery? Check.
* Client applications for multiple platforms? Check.
* Messages (the default, non-E2EE ones) sync across all clients? Check.
* Send large files? Check.
* Prevent phone number enumeration by others (who randomly add numbers to their contacts list)? Check.
* Granular privacy settings? Check.
* Search messages by text, by person, by date? Check. Global search? Check.
* Use a calendar view to check activity/messages? Check.
* Edit messages after sending? Check.
* Delete messages after sending? Check.
* Message reply threads? Check.
* User mentions and quick navigation to mentions? Check.
* Scheduled messages? Check.
* Audio messages? Check. Video messages? Check.
* Voice chats (like clubhouse)? Check.
* Polls? Check.
* Chat exports? Check.
* Media editor? Check.
* Built-in video player with playback speed adjustment and fast forward/rewind? Check.
* Edit photos after sending? Check.
* Forward messages with fine control over whether it shows as a forward and whether the caption should be included? Check.
* Pin messages? Check. Multiple pinned messages? Check.
* Broadcast channels (one to many)? Check.
* Bots? Check.
* Themes and stickers? Check.
* Message folders? Check.
* Interactive emoji? Check.
* Message read receipts (by user) for small groups? Check.
* Spoiler formatting? Check.
* Reactions? Check.
P.S.: I do not work for and nor am I in any way associated with Telegram, except as an end user.