You can certainly be a programmer in 12 weeks, but you will be different programmer than what we are expecting here.
You can also learn programming by reading 'Learn programming in 30 days'. But that is a very different kind of programming than what most people are expecting in this thread. You can learn enough programming to begin to understand how to work with software. It gives you a start. It also works if your job is extremely trivial. And I think the target audience for the book is those kind of people.
Coming to programming as a profession, in that case there are a lot of aspects that influence your full time profession, among that is giving your full learning every detail of programming and related ecosystem. Other aspects are productivity, management, analytical skills, UI design, requirements gathering, people skills. Also there are many other things required to win in practical software environments like working under tough deadlines, learning to deal with frequent stress and burnout. Keeping in touch with rapidly changing tech scenario, tools and languages. The list goes endless. I haven't covered even a percent of what I wanted to write.
Your regular data structure and algorithm sauce is probably 1% of what is required to win in practical software development today. There are 99% of other things which are not taught in books, colleges and universities. You have to learn them through experience, by working.
So just in case you think you have spent 10 years learning all the secret recipes in computer science books but are not good in other areas. You are no better than the 'Learn programming in 30 days guy'. Because if has problems in a set of areas, you have equal number of problem with another equivalent set.
This is something I have seen among so many bright, people with great academics, who don't make it big in the industry. They just don't understand so many practical aspects of the industry. Just like how 12 weeks programming guy doesn't understand all aspects of practical programming.