Star Trek's budget on TV is likely to be less than a network show with "big names" and the budget they do have can go into the look, at least until the cast becomes popular.
Actually if a show has "big names," then a higher percentage of its budget will go to cast salaries and that means less of it will go into production values. So maybe that's not the best comparison to make.
TNG was definitely a big-budget series compared to its contemporaries. Its cast wasn't very well-known at the beginning; British audiences were very familiar with Patrick Stewart, but to American audiences the most famous cast member was LeVar Burton. But because the Trek movies were performing so well at the box office and bringing Paramount so much profit, combined with the ongoing success of TOS reruns in syndication and home video, the studio saw ST as its most profitable property and thus was willing to invest top dollar in the new series, wanting it to be as prestigious as possible.
The first Abrams movie did quite well at the box office. If the next two perform similarly, that might create the same incentive for Paramount and CBS to invest in a big-budget Trek TV series.