Curious topic for this section.
If they are using a language where 100 lines of code* can make such an application which does not need to be agile then they are likely dumping resources needlessly onto it, which also brings up the next point of operating at scale is hard, quite a bit harder than many that are otherwise good at the basics might otherwise imagine (you can probably make something speak to a database, speaking to a database in a whole different data centre where lag and https://www.gamedeveloper.com/design/the-internet-sucks-or-what-i-learned-coding-x-wing-vs-tie-fighter
is in play, different matter, equally anybody not doing those are virtual machines is... actively malicious or at least incompetent to the degree that I can't tell the difference).
Couple in the regulatory compliance, management (got to stop all those people from faking others, put a thumb on the scales, weed out the kids, weed out the true undesirables...) and whatever else that comes up on that front and seems like a legit service.
Them being on the stock market usually has no reflection on code quantity or indeed quality. The stock market is a game some companies play (there are still private companies after all, some quite large ones even) and in this case them being a tech company (usually defined by them being able to scale theoretically infinitely vs my factory**, or indeed fake tech companies like wework***).
*I imagine you could do something with about 100 lines of uncommented php and mysql (we will call HTML free as the client handles that one). Good luck having that work on your shared hosting when you grow larger than a small town.
**said factory in previous generations taking the work of skilled artisans, possibly in multiple ways, and reducing artisan overhead massively, specialisation to make those artisans being the perk of cities vs hunter-gatherer/nomadic. Some favour employee to output/profit ratios as a metric instead.
***they recently imploded (later than I would have hoped but hey) but for those somehow viewing this in 5 years or more then they were a subletting company (take long property lease, resell those as short term) that styled themselves as a tech company, duped a bunch of investors that should have known better and imploded (as most subletting efforts do in fairly short order).
As far as absurd that things are public then my bigger concern for most of those is the aversion to profits, indeed most only seem to be public because they sold too much stock privately and had their hand forced. However for the next little while at least (roll on big crash) we are not seeing anybody else care about profits-earnings ratios in ways that previously made sense.