Lawyer here who has handled many family law cases. That dude ducked service back in the day, or this was one of those fairly rare cases in which people move so frequently that no one could find him. MRA/TRP folks have so badly twisted and warped the idea of family law/child support that people who don't work in it can't analyze things clearly. Things are not as unfair as it seems - once you view child support from the lens of the child, not the parent. People only imagine themselves as the person paying - and not the child who is entitled to money.
(Also, I remind you that these "unjust" laws were written mostly by men, and adjudicated by mostly men. If you want things to be more fair, as mentioned by an earlier poster, start by making sure more women make more money).
I've chased people down successfully and unsuccessfully - it takes more than just a token attempt at service to get a court to enter a default judgment. There's also a ton of paperwork involved in getting wages garnished by the state. This dude knew or intentionally chose not to know.
In the rare circumstance that he was actually in the dark about this, all states, including Texas, have procedures in place to get relief from these types of default judgments. He might be able to use them.
TLDR: Not getting "notice" is unlikely to happen to you or anyone else, unless you're intentionally making it difficult. Court documents, no matter how seemingly frivolous, must be dealt with seriously.
So we're criticizing Florida for doing what so many people in this thread want done?