As I said, the decisions are locally reasonable. However, if not supporting Firefox potentially exposed my company to scrutiny over anti-competitive behavior, then, yes, I would absolutely invest in testing procedures to mitigate that.

It's also worth emphasizing that it isn't difficult to support Firefox. I'm pretty sure that many of the sites that I visit do so largely by accident. I do a fair bit of web development, and Firefox/Chrome compatibility has never been an issue in the slightest for me. You almost have to go out of your way to choose Chrome-specific APIs in order to break compatibility. How does virtually every other website on the internet manage it—from my bank to scrappy startups with junior developers coming straight out of bootcamps—while Google with all of their engineering talent and $100+ billion cash on hand just can't seem to make it work?

> Would you increase your testing by 50% to thoroughly test for 3% of the market?

I don't think you get to make these kind of cost cutting decisions when you're a vertically integrated mega-corp who also owns the browser with 65% of the market.

In most companies, when 3% represents an in-fact huge number because you have a very successful product, you absolutely do test for that 3%.

It’s tiny companies that may ignore 3% as too expensive to worry about.

Here’s another way to answer that question: do Vimeo, Twitch, Netflix, Amazon Prime, Instagram, TikTok, etc. say “let them use Chrome” or do they manage to do entry-level browser testing? The cost increase is nowhere near 50% and clearly they aren’t willing to write off millions of users – only the company with a direct financial incentive does that.

Yes, Firefox’s market share has been declining but that’s substantially because Google spent billions of dollars marketing Chrome and promoted it heavily on YouTube, Gmail, Search, etc. Deciding not to test or optimize fits neatly into the same pattern.

_I_ would in their shoes because I'm not just in it for the money and I care about the craft.

But clearly I am not them. :-) Mathematically it doesn't make sense for Google. It might make sense from an anti-trust perspective...

At a company at the scale of Google or Facebook, yes. 3% x N billion people = a central European country or two.

Isn't that a good deal? 50% more testing in a way that can surely be parallelized to some extent does not seem a very steep price at youtube scale.

This is exactly the same situation that web developers faced with Internet Explorer 5 and 6, and it sucked for end users!

Since they throw me "Google recommends Chrome!" adverts in my face for various of their services, even when using a chrome-based browser it's not a case of only testing for Chrome/Safari. It's active work against others.