If Apple had not decided to develop their own stuff, we would not have the MacIntosh line, OS X, the iPod, iPhone or iPad, AppleTV or any of the thousands of products that they developed over the years. And all along the way people switched to the Apple products, often times taking small steps backwards at times to ultimately be moving forward.
There will be other options for what you say you must have - including, as you have already pointed out, Safari and mapping sites on the
WWW... Google may or may not get their maps app ready and into the App Store at the time of the iOS 6/iPhone 5 launch... but even if they don't, many will. And Apple has always fostered a development community that can and does meet the demands of the user base with good, reliable and innovative software. For Apple to decide to forego a part of functionality, it's well within their purview to do so. Accept it, adapt or move on. Those are your only choices.
And I at this point I can't tell of you are or are not upgrading... and frankly it doesn't matter to me... but weigh the options and make a decision... just understand that I can't fix it and you can't fix it and very few (if any) here can.
I am so done with this topic...