Hello, dontnormally! What an unfortunate way to lose. If the conditions were satisfied (road connection, entrances facing the road, available worker etc.) it could've been a bug that wouldn't show up during our test plays. Let's hope that the issue doesn't happen to you again. We'll see to it as well before the update.
When it comes to overall building vs. road placement. It's been on our minds, and we're working on a solution that would allow free building and at the same time keep the need for road connection to make structures active.
Thanks for playing the game and coming here to drop a comment!