They very much did 3 weeks ago. Not to the same degree as the smaller brokerages, but they still put limitations on margin trading, and restrictions on options.
[0] https://www.thinkadvisor.com/2021/01/29/gamestop-lawsuits-hi...
1. Increased margin requirements for GME 2. Restrictions on naked strategies
Both of these are pretty much acceptable on a very volatile stock. They never prevented you from buying the stock or options. I think including Schwab or TD in this is near misinformation because 99% of users wouldn’t make use of the features that Schwab ended up restricting
TDA is a subsidiary of Schwab and was blocking some purchases for some period of time during the week, before they put out a statement that said they "will not prevent clients from making basic buy and sell transactions".
Existing restrictions became sizable due to the market volatility. This impacted certain clients of the brokerage that had significant exposure to the names relative to their account.
Not the same thing as the brokerage implementing new restrictions.