Depends on where you live. Tech blogs were a thing of 2012-13. That was the time when everyone was into it. It is not that you cannot start one successfully, but there are big websites which has invested in the CMS and SEO mightily.
They have a lot of back-links, Ads on Google, Facebook, Twitter, Instagram etc. Their advertising budget itself is many times revenue of many small blogs.
But there is always room for a new idea. If you can think differently and present the content in an appealing manner, there is still a lot of space for you to stand in.