You are swapping correlation and causation to some degree. A country does not become industrialized by people starting to have kids at a later age. Rather, people start getting kids when their circumstances allow it: in industrialized countries, you rely less on children to provide for you when old, as there hopefully are social systems in place or you can save up on your own. Downside is, without social systems you also have to provide for yourself at old age, meaning people need to build up more savings before they feel ready for the financial burden a child is for around 20 years.
In developing countries, children often get little support above bare necessities and start contributing to the household income at a much earlier age, even before hitting their teens.
What’s your source on the reverify thing? I use matrix a lot, and this hasn’t been an issue I ever experienced anymore since they introduced cross-signing a couple years ago.
Same goes for the common clients such as element. It has been clunky in the past, but after the past major overhauls ( also years ago now) everything has been silky smooth for me, if not better than others. The one thing left I prefer from Signal is the one-time photo share.
Matrix is great, clients are great too, only the server part still is annoyingly complicated and messy. Would only recommend that for tinkerers, on that case it’s a great path to learning about the complexity of addressing lots of security concerns that others gloss over.
Edit: to add - there’s a reason why the French government and the German military decided to build their secure internal IM infrastructure on Matrix. Obviously they are hosting their own private network, but if the concept is good enough for European government and military, it is an indicator for quality especially in terms of security and privacy.