Should you be loyal to a company?

looks like a bunch of disjoint paragraphs.

(1) "your father's company" still exists, you don't have to join startup. Maybe there are fewer of them, but you can find a job there. They'll be pretty boring thought.

(2) Yes, when you join startup you often worry about finances. This is one of the part of being in startup -- you are playing the lottery, and you can lose.

(3) If you are "anxious most of the time for a price that doesn’t even scratch your balls", what are you doing in that company? Find a different one. Even a different startup may help -- they are all different.

(4) "occupants’ well-being is my utmost importance" is not always true. Often, there is no point in perfect solution if it came too late.

(5) "What is the measurement of developer’s productivity?"

(features implemented) - (technical dept accrued)

(6) "How would I know that I’m productive?"

In general, you don't. You can try compare yourself with other people, but unless you have identical tasks, it's not a fair comparison.

In bigger companies, there is a process called "PIP" (performance improvement plan). It has very specific goals ("finish tickets #11, #12 in four weeks"). If you don't do that, you are "too slow" and you are fired. If you can do it, you are not too slow.

(7) "It’s unfair on my side. As a developer, I’m already bogged down by coding alone. Making sure everything is running properly and I’m not ruining anything. "

It's 10x worse for your boss.

(8) "Being criticized for being slow is wtf."

Being criticized for being slow means you don't have a good boss. Not all companies are like that. Look around -- you can find a different one.