I wouldn't say so. RPi doesn't discontinue products, but it doesn't really make sense to buy most older models.

In practice there are 4 RPi's: the Zero (5$ is hard to beat), the Zero 2 W (small, cheap, with WiFi) and the 4 Model B.

Then there is the Pico, but it is a microcontroller, a completely different product, and the CM4, for large scale deployments.