There should almost be some sort of technological transfer to nearby empires, like cultural influence. If your neighbour is at 10000 tech points or whatever while you are at 1000, you should be able to leech some tech points from your neighbour to develop faster.

Transfer rate increases with the disparity between nations and decreases with distance.

So a super advanced empire on continent A will contribute to nations on continent A and B, but those on continent A get more of a bonus than those on B.

This aligns fairly well with reality as neighbouring countries would transfer students to universities all the time, less so the further the nations are apart.