You can be buying both. E.g. used LEGO Death Star II sets seem to go for around $700 on eBay (~$1500 new), and similarly if you buy BRIO train sets for your kid

You can be buying both. E.g. used LEGO Death Star II sets seem to go for around $700 on eBay (~$1500 new), and similarly if you buy BRIO train sets for your kids you'll both get better quality and something you can re-sell at a reasonable price, v.s. say buying crappy IKEA train sets. After having kids I've seen the sheer amount of crap in excessive volumes that gets gifted to kids. Everyone would be better off if kids got 10x fewer toys of 10x more quality.