There are several factors that come into play here:
Element of surprise / reaction times. If whoever has the element of surprise is most likely to win a conflict, then yes, it would increase the frequency of warfare and conquest. Until reaction times to these sorts of assaults were improved, such that the element of surprise were lessened, this would remain the case. This is why the marines in the Aliens franchise use motion detectors to assist them in knowing whether the aliens are approaching; once the aliens get within visual range, they make quick work of humans. Similarly, it may be that your teleportation technology requires a large energy build-up in order to teleport a sizeable force. This may mean that it could be detected by opponents before it happens.
Cost. Finance is about managing risk, and this includes financing wars. Ultimately if the proposal looks good, the risk of being struck at first is high, and ethics are not in question, then a quick, first strike may be justified.
Level of paranoia. This again relates to the general level of ethics in the world (c.f. adherence to institutions like the Geneva Convention). If paranoia is high, then yes, it is highly likely that lethal first strikes would become commonplace.
Centralisation / deployment concentrations. If attacking capitals became commonplace, societies / nations would become more decentralised. It may also serve to decouple military administration further from civil administration. If an opponent aims for your heart, have more than one. This also leads to forces being deployed according to the risk factor inherent in not defending a particular facility.