While I find the premise of the blog post to be potentially interesting (2nd post since 2011), I wonder if this is much more than a thinly veiled advertisement.
The good news is that some good questions have been asked, and the reply will be available for scrutiny.
I'm not sure Cornyn was the best member of Congress to write this sort of letter. Yes, he is on the Committee of the Judiciary, but his political leanings might result in posturing that obfuscates the issues we care about. That being said, I'm glad someone asked.
One premise the author stated is "cutting your spending rate is much more powerful than increasing your income". The idea seems to be that this both increases one's ability to save while also lowering the bar for current and future expenses. Many people could benefit from taking a hard look at their expenses and trying to find areas to cut.
That being said, taking this orientation has its limits. First, there is a floor to how much savings one can make on a given lifestyle. Additionally, the upside potential is limited if a lot of time and effort is spent on trimming expenses.
Some folks, especially the type of folks who frequent HN, have substantial opportunities to increase their income (e.g., through freelance work) that often suggest that increasing income is MUCH more powerful than cutting one's spending rate (I think patio11 has mentioned something like this). Often times the equivalent of one or two hours of tech consulting can cover the cost of many "unnecessary" conveniences that save one time and/or effort. Additionally, it's much more scalable -- that is, the upside of saving more of an increased income frequently has more upside potential than cutting costs.
Of course, not everyone can do tech work, and even tech workers will probably need to adjust their spending to a lower level once they are on "fixed income", but I think these lines start to stray from the central issue.
As for startups, I think a holistic approach to assets and resources needs to be considered. Specifically, often the scarcest asset is founder time, so spending money to save founder time is often an <i>extremely</i> prudent choice to make in terms of adding value to the company.
This site has a lot of interesting tasks in many languages. "100 doors" and "24 game" are good starters. "Minesweeper" (text-based) is a little more involved, but it might be what you are interested in. Sudoku games and solvers are lots of fun.
Making a text-based chess or go game (no ai) could also be an interesting challenge.