Why did MMS feel so janky back in the day? Was it a client thing or a protocol thing? Whatsapp felt so responsive back in the day. I'd be pinging my family in

Why did MMS feel so janky back in the day? Was it a client thing or a protocol thing? Whatsapp felt so responsive back in the day. I'd be pinging my family in real time halfway across the globe on mobile in 2009. For Free. That was a killer app... Why did MMS fail where Whatsapp succeeded?