They are preserved indefinitely, the entire transaction is stored in the block and removing the signature would invalidate the block’s hash.
In Bitcoin, Segwit was the thing that changed this, but non-Segwit transactions likewise include the signature in the block forever.
It’s not really a problem in Ethereum because the limiting factor on an Ethereum block’s size is gas, not the actual size of the transaction data.
Is that what it’s called now? An xeet? LOL
They are preserved indefinitely, the entire transaction is stored in the block and removing the signature would invalidate the block’s hash.
In Bitcoin, Segwit was the thing that changed this, but non-Segwit transactions likewise include the signature in the block forever.
It’s not really a problem in Ethereum because the limiting factor on an Ethereum block’s size is gas, not the actual size of the transaction data.