I guess it comes down to to whether you think that similar situations breed similar solutions. Every major power borders 2 other successor states and has an outer (periphery) border. So also do the Taurians. Every major power has to deal with pirate raids on its periphery border. The Taurians are well noted to have a pirate problem. Every major power has to deal with raids from neighboring powers. The Taurians are no different in this either(whether those raiders are Capellan or FedSun). By 3000, every major power has a shortage of battlemechs. I have seen no references to indicate that the Taurians have more battlemechs than they know what to do with. Every major power that has chosen to defend on the ground, like the Taurians, has, in order to address the battlemech shortage, turned to the MBT as the alternative.
So why do the Taurians not have an MBT? Thinking about it, the Taurians should have already been producing some form of MBT before any successor state. The reasoning being that with a smaller economy, fewer resources, and having to deal with pirates sooner than powers closer to the core, the need for a cheaper, more easily produced alternative to a battlemech should have come up sooner rather than later.
Looking at the problem from an economic standpoint, the MBT may well still be a better choice than the alternatives. A 3025 era locust still costs around 1.51 million c-bills, or 6.05 million per lance. Kit recommended an LRM + SRM carrier combo (specifically a heavy LRM crawler carrier, the SRM carrier wasn't specified) but that isn't cheap either. The standard LRM carrier runs 1.87mil c-bills, the heavy 2.94mil, the SRM carrier costs 1.93mil and the light model 0.84mil. So a 3 LRM carrier + 1 Light SRM carrier in a lance = 6.45mil per lance. The Exael MBT in the fan design forums costs 1.34 mill each, or 5.36 mill per lance. Seems to me that making a proper MBT would be cheaper than battlemechs or missile carriers, more effective than missile carriers, and would survive better than missile carriers placed in the same role. Wookiebear advocated static defenses, which is an excellent idea, but is very limited in scope. The biggest problem is that static defenses are well, static. This gives attackers an easy target (4 point bonus to TN) whose only option for survival is additional armor. Problem there is that no matter how well protected a fortification becomes, the opponent can always leave, and come back with a bigger gun. Or they can go around the fortification, or even blind the fortification with say, smoke, and just walk on by... When a few battlemechs with a couple tons of smoke LRM ammo can nullify the backbone of a defense it makes me question how good this defense really is, and how I can make it effective, and I haven't even done a cost analysis... The alternative, you guessed it, an MBT that can move out of the smoke.
In the early publications, the Taurians were thought to be producing the Rommel. That information stood as canon until specifically corrected. However, this meant that the Taurians did have an MBT as part of their original defensive plan. Later, when the Rommel was removed from the Taurian force lists, it left a gap that no other Taurian vehicle has been able to fill, resulting in a devolution in tactics as the Taurians have been pigeon holed into more expensive, less effective alternatives. Do not take this as an effort to allow Taurian production of the Rommel/Patton. It has been stated over and over that they do not, I understand that. However, there is a big difference between "The Taurians do not produce the Rommel/Patton" and "The Taurians do not produce ANY main battle tank(s) whatsoever." This brings me (finally) to the question asked by the poll.
I think the Taurians have a pair of successor states on their border, either of which would be quite happy with some extra battlemech production lines and the materials to operate them. I think the Taurians have a pirate problem that needs the kind of attention that a big weapon, inflicting high single impact damage to a light/medium battlemech would do wonders for. I think the Taurians have a need for a vehicle tough enough to take hits, powerful enough to dish it out, and flexible enough to work with whatever forces are available, against whatever opponents show up.
In short, I think the Taurians need a main battle tank.