They have, but the limit of people in a group is significant lower then Telegram, at least for signal\ws, dont know how matrix handle this. Telegram allow 2000

They have, but the limit of people in a group is significant lower then Telegram, at least for signal\ws, dont know how matrix handle this. Telegram allow 200000 members in a chat group. Signal on the other hand allow only 1000 and ws limit is 1024. It is possible to have group chat encrypted, but this does not scale very well and allowing new members to see older messages also is trick, although both are possible. EDIT: i just checked for matrix and while they do not impose an limit their docs do indicate that there are performance problems for very large groups with tens of thousands of members, that while much bigger then signal\ws it is still much smaller compared to telegram.