You're not really giving the whole story here.
A lot of people slapped a 'Don't use IE, it's old and broken message" on their sites because it was old and broken. Generally this didn't show for newer versions – though you're right in that a minor number of 'douch-baggy' sites did.
It was a significant and in some cases crippling workload to support end-of-life browsers that were lacking features such as e.g. transparent image support. Telling users to upgrade was a perfectly sensible thing to do in these cases – if it was suitable message for your customer base.
These days the situation is very different. There's almost definitely no way that the Play store doesn't work on Firefox. It's almost certainly being deliberately excluded from accessing the Play store for what can only be described as malicious reasons.
UPDATE: Update 9:05 a.m. PT: Google has informed VentureBeat that the issue experienced by Firefox users on Android is a bug, and a fix will be issued “very soon.” http://venturebeat.com/2015/02/10/google-play-no-longer-supp...
The aftermath of all of this falls on the developer's shoulders, which is why so many hours are poured into getting a modern webapp to work across all browsers. Resources are limited, and at some point, developers have to throw their hands up and resign from having support across all browsers.
When you start using a seemingly mature HTML5 api, and find that it doesn't work as expected in all browsers, what recourse does one have? Should we continue to stifle innovation while we wait for the browser vendor to reach compliance? History shows you're going to be waiting for a while, or for ever.
File bugs. Chromium and Firefox are not black boxes.
A few examples that come to mind:
https://code.google.com/p/chromium/issues/detail?id=67587
The problem is we let web culture degenerate into a "my browser or the highway" attitude thanks to the fuel uber-geeks poured on the IE6 fire. Now we're constantly reaping this negativity. I won't even go into the issues I've had with Opera, AOSP browser, dolphin, midori, and others. This "my browser or the highway" attitude is still very strong and we need to stop pretending its a legitimate way to manage the web. No wonder people are clamoring for walled-garden app stores and dumbed down apps. Maybe they're sick of the geek-led browser wars that flare up every so often. Google knows this and is using this to its advantage with its long-range plan to lock people onto its proprietary Android-based services. Now here's another reason to not use Firefox and to stick with Chrome.
Based on your argument, I think it's time for the opposite.. stick with Firefox
Take your points, but in fact, Microsoft didn't refuse to support web standards.
IE6 was more standards-compliant than Netscape when it came out. The main problem was that Microsoft stopped developing browsers (for complicated reasons that must include the US anti-trust suits). That put it years behind in standards support.
Then when it started to catch up (with new browsers in Vista, Windows 7 and Windows 8), it couldn't move users on to later more standards-compliant browsers, even though it tried.
The main reason for not supporting IE was its anti-standards stance, not its market share. I think that's a perfectly valid reason, just like saying "I don't want to support Chrome because of its promotion of DRM in browsers".
It's simply not true that IE wasn't adhering to standards, or had an "anti-standards stance". It is true that IE6 didn't support standards that were developed after it was released, but that's also true of every program released (until it's updated).
Not saying Microsoft didn't make mistakes, but that wasn't one of them ;-)
There's been this largely ridiculous "revenge of the geeks" after the IE6 days. Now we've fed so much fuel into that fire, that casually telling people to use different browsers is the norm. I'm not saying I told you so, but.. I told you so.
Instead of focusing on your customers' needs, we just ran with what's popular. That's always going to be a losing strategy.