Protocol design is popular "these days" so everyone eventually chooses UDP, and reimplements a subset of TCP in their own protocol. (edit: not everyone needs state in their protocol, but everyone needs to implement rate limiting)
If you're unaware of a large interest in protocol design, or don't understand the cost and complexity of DDoS attacks, what point were you looking for?
If you're unaware of a large interest in protocol design, or don't understand the cost and complexity of DDoS attacks, what point were you looking for?