Even if you develop for Chrome, Firefox and Edge you'll just end up building workarounds for all 3, not adhering strictly to the standard.
The standards are a single source of truth for your production, if you build solely to a single browsers quirks (in this case Chrome) then those quirks can change at any time.
I still fix FF bugs when they come in (it seems to be a bigger offender than IE recently) but developing for Chrome first is the only approach which makes business sense.
It adds very little extra work with the advantage of surfacing edge cases/issues that might have bitten me even if it was just Chrome in the mix.
Also from a business risk point of view tying the entire platform to a capricious vendor is dangerous and I've been around long enough to remember the days of IE5 then 6.
Once bitten, twice shy.
A web developer codes against real machines, not the imagined, idealized, and non-existent machines the specs describe.
Regardless of browser matrices, it is the will of the developer to support the open web platform that made sure that Internet Explorer and thus Microsoft didn't own the web (browser) in the 2000s.
Anecdotally this point of view has done no harm to me and I'm not the only that shares it.
The reason web developers care about those customers varies from dev to dev. Some believe there is value in a heterogeneous ecosystem of browser implementations. Some have a few high-value customers who refuse to switch (or, in the case of e.g. Microsoft, cannot switch because enterprise constraints are restricting what browser stack they're allowed to run).
But the point stands that when you support multiple browsers, you don't approach ideal user experience (in terms of performance and reliability) for all your customers by throwing your fingers in your ears and proclaiming "That browser is out of spec!" when you find a quirk---you do what you have to do to make your code run on, around, or in spite of the quirk.
And then what?
> And then what?
Build to standards first, then accommodate quirks last.
Building to Chrome first is just building to its quirks, and totally forgetting about standards.
"Write HTML, test on Chrome" - what people do in practice - seems to fit "build to standards first, accommodate quirks last" just as well as "build to Chrome first".
I just write standards compliant ES6 code, put it through a transpiler and some polyfills, and my code runs on every browser. I haven't had to think about which browser I'm targeting for years.
... but you can (and I'd argue in a lot of cases, looking around at the overly-complicated sites on the web, should) write a lot of fully functional web pages by keeping to the standard and trusting it's good enough. We are no longer in the bad old days where IE and other browsers deviated significantly---most of the browsers today adhere closely to the spec, and in the places they don't, it's often more like one browser handles a nasty corner case better than another because the browser built an optimization in for a critical path your page layout cares about.
