Block size is in a sense still increased, well that depends on your definition. Blocks are definitely bigger than 1MB right now.

The most important period to look at would be the block size debate a few years back. One camp thinks that a hard and fast block size increase is the solution whilst the other thinks that second layer scaling is the future. Then again, how much should we really increase the block size? Can it ever be sustainable? The point about a unsustainable block size increase would be that we would reach a limit where only large entities can run Bitcoin nodes, delay across transaction propagation, etc. There are tons of supporters of both sides and they all have their concerns and their vision to what Bitcoin really is.

If you want the actual answer, then it boils down a lot more to politics rather than what we can or cannot do.