Usually SICP is recommended as a follow up to HtDP. It's freely available at https://mitpress.mit.edu/sites/default/files/sicp/full-text/...

I wake up early at 4AM, make a cup of coffee for myself, play 15 min of chess and study Spanish for another 15-20 min. This routine gets me ready to do intellectually intensive work like reading a hard technical book.

Same exact thing happened to me at Microsoft during the system design interview round. Interviewer wouldn't just let me explain and kept on arguing about a relatively minor issue and wouldn't let me proceed and in the end failed me because I didn't come up with a good design. Really the whole 45 minutes were like him repeatedly stopping me and coming back to that one issue.

I noticed I spend too much time reading wikipedia articles, jumping from one to another, so I built a chrome extension to limit that browsing time to a few minutes per day.

That I am not good enough to do the things I dream of doing.

Or Which may be exactly what they want.

I've been making a Django app for over a week because I wanted to learn doing web dev. I hope to finish it another 2-3 weeks. So far, it's been a intimidating and yet fantastic experience learning about django, http, html dom, js, jquery, css, bootstrap, sqlite, orm, templates and such.

Lol at the third category - they're at the wrong jobs(for them), perhaps they need to do something on their own, figuring things out themselves!

To me, it looks like you're just having problems with algorithm interviews. I have a solution for you and it's much more effective than textbooks - go to websites like www.spoj.com, projecteuler.net, topcoder.com and many other similar online sites, I suggest www.spoj.com - start with the easiest ones (on most of these sites, problems are tagged by their difficulty level) and solve them - I mean code solutions to them in a language of your choice (But C, C++ and Java are popular in interviews) - these sites have online judges where you can submit your source code, have your code run against a large suite of test cases for each problem and get results back - all in a matter of seconds.

Solve 100s of these problems(start with easy ones and move into harder ones at your ease, learn new concepts and algos as you go) and try the interviews again in another 6 months. I promise, you'll improve a lot at this kind of problem solving. I've seen a number of people do this and succeed at algo interviewing game.

I've never worked in an early stage startup, but what is it exactly that those working more than 100 hours per week do?