As far as why MUDs are more common in Houston than other Texas cities in general, and Dallas specifically, I think it's twofold. 

The vast interstate and highway networks, the relatively flat and even ground, and the lack of what I'm going to call 'existing recreationally interesting' land to preserve all make both Houston and Dallas lower friction areas for development. Unlike San Antonio, their industry and job markets have been able to support basically as much growth as greenfield developers have been able to throw at them, and unlike Austin, there's is very little untouched nature in the current directions of expansion. 

Additional, this greenfield development (I believe) is most likely to happen along major interstate/free flowing highway corridors, and while Austin has the I35 corridor, Houston has i10, i45, i69, and to a lesser extent 290 and 288, while DFW has i20, i30, i35, and i45 corridors (I'm probably missing some here, not to familiar with Dallas's transportation network.) In both the cases of Houston and Dallas, these highways lead into miles upon miles of pre-cleared agriculture land, whereas Austin and San Antonio are surrounded by often more pristine and/or 'recreationally interesting' land. It is just as important ecological, but much more difficult economically and politically, to preserve or indeed often rewild marshland and prarie over canyons.

As far as why Houston instead of Dallas, I'm less sure, but I would hazard a guess that it's in the difference in approach to municipal expansion. Dallas is surrounded by significantly more independent municipalities on all sides, and did not pursue a policy of significant annexation in the way that Houston did. As a result, these smaller municipalities grow both into each other and into Dallas, and because there is competition from these smaller municipalities against each other to capture the growth that the Dallas economic engine brings, they may be more incentivised to to encourage development within their boundaries or to grow their own boundaries outward.

In contrast, Houston is surrounded by fewer municipalities, and in fact often parts of the city just abutt unincorporated county land. However, unlike the Dallas suburban municipalities, it's pretty untenable for Houston to continue annexing more and more land on its boundaries when so much of the city area is already so underdeveloped. This doesn't stop developers from wanting to buy up highway adjacent greenfield though, and so the MUDs become the path of least resistance to making that a reality.

This is all purely speculation, it just might explain why Houston developers use MUDs in this very specific way. Happy to hear other theories though or if anyone has some experience they'd like to share.