Here again, Flash works perfectly fine with Firefox, but Mozilla decided to boycott it, so they forbid Flash from running in their browsers, just like Apple did in their mobile devices. It is not incompatible - it's just being blocked. Don't know if you remember, but Mozilla's president made inflammatory claims against Flash because it's not open source. In 2012 they released a limited open source imitation of FlashPlayer called Shurnway, based in HTML5 and JavaScript. As with almost everything HTML5, they couldn't make it work and it was discontinued. Google did a similar thing with their homemade Pepper Player, which was created to replace Adobe's FlashPlayer, and at the same time forbid its installation. For years, Google Chrome users complained about Flash contents crashing, which Google promptly blamed on Adobe, accusing FlashPlayer when in reality it was their own hidden Pepper Player that was crashing. When Adobe finally published the Pepper Player scheme, claiming not to endorse or support it, Google strategically removed Pepper Player from Chrome to clean up their mess. The problem is that Google "forgot" to let people know it was their own fault that Flash was crashing in their browser. That has worked to their advantage, but it was still a lie.
It's important that people know that Flash is NOT incompatible with browsers, but instead it is being deliberately blocked and sabotaged. Mozilla and Google have benefited from making Flash contents crash in their browsers for YEARS by using homemade versions of FlashPlayer, without people knowing or acknowledging it. They used these to convince people that Flash was evil, when in reality they were the ones causing the crashes by replacing Adobe FlashPlayer with their own players.
Apple's best shot is to claim that Flash is "obsolete" because it's "old". Well, then Photoshop is even more obsolete because it's older than Flash, and we should all ask Adobe to remove it from the market. Not only it's very old, but it's definitely NOT open source. Then Apple claims that Flash is big and slow. Well, so it's Photoshop. Then Apple claims Flash is a "security risk", while they are yet to present a single case where that was true in over 30 years of Flash existence. Like it is with Java, Flash runs in a secured sandbox using a virtual machine, which makes it impossible for people to use it to cause harm. The so-called "security risk" Apple was referring to was the fact that some people use Flash to make annoying blinking animated banners, which can also be done with plain animated GIFs, so it's not Flash's fault. It may be annoying, but it's definitely not a "security risk", and we don't need Flash to make annoying banners. Then Apple accused Flash of being able to go to full screen mode, now claiming that to be a "security risk". That is also not true, because Flash can only switch to full screen mode if - and only if - the HTML code on the website allows it. Flash cannot force it on its own.
These allegations are simply not true. The truth is that Flash has dominated the web apps market for decades, making 75% of all interactive contents in the world. Is that a coincidence that Flash only became evil after Apple decided to start an app store? Is it coincidence that Google only started to demonize Flash after they decided to start an app store? If you can't compete, you either buy it or kill it. Is it that hard to connect the dots?
Finally, Google is the biggest proponent of HTML5 in the world. They truly tried to make it work in their sites and services, but after spending millions, they quit a year later. They are definitely not badmouthing HTML5 - it simply didn't work for them, and they lost a lot of money trying. SMS also tried with the new Poser 11 library, but to this date they still couldn't make it fully work. Simple things like navigation and even drag and drop are still broken, and they gave up trying to fix it. In addition, Google have already clearly stated that HTML5 cannot replace Flash because of the low performance limitations. They just want Flash out of the way, but propose nothing to replace it. The same goes with Apple, who just want Flash out of the way, but offer nothing to replace it. As usual, they push HTML5, in contradiction to Google's official statement. This is about removing the competition - it has nothing to do with being old or obsolete. If it were, they would be offering a substitute, but nope. They offer nothing in return.