Side note, have you seen Magna-Tiles? My 4yo son loves them. They have magnets along the edges so you can easily stick pieces together and build structures. They are bigger than regular LEGOs, more along the lines of Duplo. And they can be pricey, but they are tons of fun for little ones! Especially when their favorite thing is to knock down whatever you build.
Duplo seems much more in the spirit of Lego sets from the '80s. Builds used fewer, but larger pieces. I enjoyed playing with the older sets because you could tear them apart and put them back together much more easily.
Newer sets look nice, but IMO are much less fun to play with. My kids still like building Lego sets, but our Duplos get played with more often.
Duplo is interesting, it allows kids to quickly build pretty massive stuff if they have enough of it. But mine were done with it relatively fast and we ended up donating it to other people.
We have a large box of duplos but my three-year-old isn't interested at all, maybe showed some interest a while ago, but mostly to build the tallest tower. Now it's time for the real legos, but I'm not sure if we'll even get any if she won't play with them.
My 2 year old daughter hasn’t really shown any interest either.
It’s weird, as a kid I wasn’t really into building stuff. Lego, wood blocks, etc. The only exception was “forts” in my woods. I could play with my Power Rangers toys for hours.
Even as an adult, Duplo is underrated. It's a lot of fun to noodle around with creating things in Duplo because there are more constraints and you can build a rough simulacrum of something in only a few minutes.