Third party browser & JavaScript engine + ability to install web apps on the Home screen = third party app store that doesn’t have to pay Apple’s fees.
When Apple could force everyone to use Apple’s WebKit, web apps didn’t matter as much as Apple could limit WebKit features to push people to the App Store. E.g. it took ages to get push notifications on WebKit. If Google and Mozilla are free to make whatever improvements to their browser engines, the need to have native apps on the phone decreases considerably.
He pushed everything into apps though. Getting rid of flash was a big part of that because JavaScript wasn't capable of all of the same things at that time. The canvas wasn't fully supported yet. That meant games and anything with crazy animations needed to be an app.
Killing flash was one of the first steps to where we are now. It may not have been perfect but it did a lot for its time.