A feature peeked at Ways of History: in games with independent bulbs accumulation per tech, let it be possible that certain percentage of bulbs committed to the current research target (25% in that game) is distributed among other currently researchable techs. I.e., if in the start of the game you can research one of 8 techs and produce 4 bulbs towards Pottery, some other tech (priority is either random or some function from tech and turn number), e.g. Masonry, gets 1 bulb. That can make technology progress more predictable and some holes in it less exploitable.
A feature peeked at Ways of History: in games with independent bulbs accumulation per tech, let it be possible that certain percentage of bulbs committed to the current research target (25% in that game) is distributed among other currently researchable techs. I.e., if in the start of the game you can research one of 8 techs and produce 4 bulbs towards Pottery, some other tech (priority is either random or some function from tech and turn number), e.g. Masonry, gets 1 bulb. That can make technology progress more predictable and some holes in it less exploitable.