There are several possibilities regarding technology.
In most cases, the species encountered are space faring races and are encountered in space. The technology they use makes life in space possible or at least more bearable.
- The transporter eases planetary exploration and transfer between vessels.
- Replicators eliminate the need for large cargo areas filled with food and water.
- Universal translators make it possible to talk to members of other species, even if they were only just encountered.
- Holodecks/Holosuites allow for entertainment and a form of "shore leave" without leaving the ship.
Natural Progression of Technology
Many of the different technologies operate under similar principles and could be seen as "the next logical step" once the precursor technology had been perfected.
- According to Memory Alpha, the replicator is a variant of transporter technology that simply materializes matter in a different form.
- Holograms in all their forms (holodecks, holosuites, the EMH etc) use force field technology are a variant of the shield technology that protects the ship in battle, keeps prisoners in the brig, keeps shuttlebays compressed when the external doors are open etc.
- Subspace technology is used to both propel the ship at warp speed and to communicate at great distance.
In some cases, we've seen that some races had technology or more advanced versions of technology before others. In those cases, the "lesser" race either acquired the technology or eventually developed it on their own.
- On Enterprise, Tucker said he would like to get a look inside the nacelles of a Vulcan ship because it had a higher maximum speed than Enterprise did. The Vulcan captain refused but humanity eventually "caught up" to Vulcan propulsion technology.
- In the episode Dead Stop, the Enterprise crew observed and used replicator technology on the repair station. That may have prompted the eventual research and development of the technology by humans/Starfleet.
- The Klingons acquired holographic technology from the Xyrillians in exchange for not killing them.