Telegram is important if you get your news from sources outside of the 'Anglo American empire'. People all over the planet use Telegram to curate their own news feeds and cultivate their own communities. This is generally done with a view to promote understanding rather than to spread misinformation. Telegram is great if you want the perspective of 'the other side' or 'both sides' if you 'trust but verify'.
Some people can get the Telegram app and never get to find any of these communities to never understand what Telegram is really about. Usually though, channel owners repost from other channels and promote channels they like. If you follow one channel then it should not be hard to find other channels in the way. You can also see what other people are subscribed to, depending on their privacy settings.
Importantly, there is no algorithm on a home page, urging you to sign up for promoted content.
As for 'where does the money come from', there are ways to subscribe to get a few more bells and whistles, with many that cultivate a community choosing to do so, in order to manage their channel(s). Few normal users pay up, and the app isn't paywalled or 'pay to post'.
There is a whole parallel universe of drug dealers and women that sell their bodies, all of which is a search away. I doubt these people are paying for premium accounts either.
IMHO only a modest amount of money is needed, sure, bandwidth has to be paid for, however, the app is already written and it is very good. I have no idea why the likes of Meta need tens of thousands of 'engineers' for optimising doom scrolling 'with AI'.
With Telegram, you could have 1% of 1M users paying $10 a year, meaning revenue of $100k a year. That would be okay if it was Pavel and his bro in his mum's basement with one server to pay for.
Scale this up to a billion and now you are talking. Since the app scales, are more staff needed? A few devs, but not that many managers since the founders are technical and therefore don't need the useless hordes of non-technical managers. Yet the money is now 1% of a billion. Multiply that by $10 a year, every year, and Pavel ends up asking finding his Bugatti on the moon.
This sounds manageable to me, no need to run in debt, have shareholders or be beholden to vested interests.
At Meta et al., there is a need to feed the greed of the stock market, pay billions in debt, do billions in share buybacks, do the AI nonsense, keep the advertisers happy, keep America's Greatest Ally happy, sign a secret deal with Five Eyes and the list goes on.
I have never met Pavel or the Meta guy, whatever his name is, but I suspect the former is getting more out of life than the latter.