I started this blog on Dec 2014. I've been writing for about two years (and some months) and have published about 190 articles. I think I have enough experience to comment if you should or shouldn't start a technical blog.
First, let me start off with the harsh aspects of blogging.
The hardest part of blogging is making writing a habit. I love writing, but I must confess that writing regularly has been quite a challenge. There are times when an influx of writing energy flows through me that I end up writing a post a day. Other times, I go weeks or months without writing a single post. I used to fight this writing drought by forcing myself to write, but I realized that writing is like music. When it comes, it comes; there is no point in pushing it.
No rewards for a long time
This past January I got about 3.5K visits. That is the highest number of visits I've ever gotten in a month. However, during the first year, my average number of visitors was less than 20 a day.
Be prepared to write and have no one read your articles. This fact brings me to an important point; your purpose should be to HELP readers, not be concerned about your blog stats.
If helping your readers, even if it is only one, brings you satisfaction, then blogging is for you. Else, do yourself a favor and find another hobby.
Now, let me share the positive of having a blog.
Your writing will improve
Writing is a skill. You need to practice it to improve it. Blogging is the perfect stage to practice this skill. I have noticed a huge improvement in my writing. If you go back to my articles written around 2015 and compare them to recent articles, you will see improvements; not only in clarity but also grammatically.
You get to help people
Helping others is the one reason that makes blogging worthwhile. I feel an enormous sense of satisfaction every time I get a message from a reader thanking me for a post or asking for advice. This type of satisfaction is hundred times more rewarding than seeing your blog stats improve. A "Thank-You" message from readers like you, makes all the trouble of writing an article worth it.
You will become an expert
It is interesting how cracks in your understanding of a topic emerge once you start teaching others. As a matter of fact, It was writing that improved my understanding of game engine development and allowed me to complete my project.
I modified the engine's architecture several times after writing an article. Writing and teaching solidified my understanding and gave me ideas how to improve the engine. Teaching, not coding, enhanced my computer graphics knowledge.
So, should you start a technical blog?
If your goal is to express yourself through writing and you have an honest desire to help others, then blogging will be rewarding. However, if your goal is to make money like some bloggers have been able to, then be aware that the money will not come that easily and it may take a while.