Implicit here is the claim that giant companies do hilariously dumb things a greater fraction of times than small companies, but I have seen absolutely zero evidence of that.

If you think the buttons in Gmail are bad, check out the UI of almost any site or app made by a randomly chosen small company. Doing things well is hard and doing things not very well is often sufficient. We take for granted that small businesses are kinda crappy at almost everything and yet still we get what we need done and the world moves on.

For example, my local luxury chocolatier is Theo. They have a very nice looking website. Take a look at the chocolate finder: https://theochocolate.com/chocolate-finder. It tells you to input a "postal code" which to most means a zip code (https://en.wikipedia.org/wiki/Postal_code). But when you type in a number, it tries to autocomplete addresses so you end up on some random street at an address that starts with your zip code. This is literally me picking the first small-ish business I could think of and clicking around for less than a minute.

We notice the mistakes of giant companies because we spend 99% of our life these days interacting with them and because the mean quality out of giant companies is somewhat higher, so the mistakes stand out as relatively worse.