Good call! They have info on general population which shows about double the number of horses I originally thought (at least in 2016), and declining at a good clip of 10%+/decade) . So drop is still large but just a bit smaller.

The general point is before cars horses were used a lot, entire industries were based around them and our now gone. The toy factor does not compensate because of cost and inconvenience of owning a horse.

0 - https://datapaddock.com/