At low levels, scrolls are balanced in cost by the fact that wizards also want to be adding spell to their spellbook. It costs 125 gp to add a a 1st level spell to your spellbook (assuming you have to buy the initial scroll). That's a lot of scribing you can do, but having spells in your book is great.
By higher levels, scrolls start ramping up in cost just like any magic item. And the caster level, DC hit tends to be worse.
I'm playing an archvist at 3rd level. I make lots of scrolls and they come in handy, but its also a decent drain on the party's overall funds. I think its balanced.
As for the time to scribe scroll debate, I think the rules side with multiple spells on a scroll. Heck, even the scrolls in the DMG that players are designed to find have multiple spells on them. And the crafting rules do say 1 day per scroll, not per spell. That might have been their intention, but I think the rules side with 1 day per scroll, multiple spells per scroll.