UDP is connectionless, it just sends data to <somewhere>. Doesn't care if that somewhere is online, or available, or exists at all.

If you don't check for returns, TCP isn't going to help either.

The requirements you listed don't make sense as written. Nobody would ever use UDP.

TCP establishes a connection when it starts and it has build-in timeouts (and various mechanisms) to detect dead connections. TCP will signal to the application if the destination is unavailable or lost.

The requirements make sense and the common usages for UDP fit these requirements.

It's correct that [almost] nobody ever uses UDP. It's a niche protocol for a very few specific use cases, one of which is real-time FPS/RTS/MOBA games (which fits all the criteria I listed).

> it's correct that [almost] nobody ever uses UDP

Skype, Facetime, WhatsApp, Hangouts, Telco VoIP, Facebook Live, YouTube Live, Surveillance Cams, most VPNs.

TCP by itself does not detect dead connections.

while its technically not a timeout, it is stopping the network traffic

the TCP packets require an ACK ever n packets, as defined by the FREQ field. If the ACK isn't received, no further packets are send.