I would not call that spike in difficulty "little".
0.14 blue science was difficult to get started (maybe two or three times harder than green) but once you had just a few blue science machines, you could start doing bots and do everything more efficiently.
0.15 blue science is easy, barely a step or two above green, but you don't get requester chests from it. Meaning you're stuck with belt chaos until not even purple science, but gold science.
The steps in between are evened out, but the amount of setup required to automate all of these additional science packs requires A LOT more space than before. At least double, maybe triple the amount of space to get any amount of these science packs. It's to the point where logistic network is almost moot and comes so late in the game, that there's nothing left for it.
It's a similar problem to get electric furnaces; you either build a huge coal-powered smelting setup in order to generate enough resources to research it quickly (but by then you might as well just keep using the existing setup) or you try not to waste too many resources on steel furnaces by building smaller smelting setups, and end up taking forever to get to electric furnaces.
But at least the furnace problem is remedied by the fact that you will eventually need to expand smelting, as 0.14 blue science was only about 50-70% up the tech tree. 0.15 gold science is REALLY near the end of the tech tree, maybe 80-90% of the way, up so there's hardly anything left for bots to do by that point. Unless you feel like tearing down the whole thing.