I do not think there's anything wrong with TMLs. Yes, they can be strong if your opponent is not ready for them. Especially remote extractors are often good candidates. Which is fine in my opinion - if your opponent is being greedy then TML is the tool that is available to you to punish your opponent.
What I think @SainseRow is referring to is that TML (just like SML) scales quite decent with the number of players. And as a result, you need more TMD (or SMD) and therefore they look expensive. But usually my problem is not with the costs of a TMD, it is the lack of a tech 2 build suite in the area where it is required.
@caliber said in TMD could be cheaper:
The problem here is not the TML being too strong or that TMD are too expensive. The problem is that the opponent team let white build the TML in the center of a 10x10 map. Especially considering that they have a lot more units in the area than white does. They let you to sit there with a TML. And that's good mechanics working - white takes advantage of its opponents being too passive. Good on white for doing so.