>If they're so standard why do people develop for Chrome and ignore other browsers?

Because in practice each browser is a separate app platform with support of different features and with different performance profiles. From a business perspective for a business to expand to a new app platform there must be some sort of justification to do so. As an extreme example think of why don't websites also remake their site on Roblox for example? Supporting a product on an app platform well is expensive and not all platforms can justify that expense.

But ... i thought Google was standardizing the web.

Would they be introducing features to their browser at a speed no one else can match just to create a lock in effect instead?

And are those features benefiting every site or are they targeted towards Google properties?