Do you need a paid plan to launch a Shopify Store?

Previously I was able to create a free development store and was able to launch it and receive up to 50 orders before having to switch to a paid plan. This was about a year ago.

I tried to launch my new store and I couldn't unless I switched to a paid plan. Is it not possible to launch a development store without switching to a paid plan now?

No. Around March 2020, Shopify decided to disable payments on developments store. They even removed the ability to disable the password. So, as you said, you will need a paid plan if you want to hve your store running.