There are already calls for another stimulus bill, because the first hasn’t been too effective. Why hasn’t it? A. J. Strata has a big hint here.
The bottom line: in order to have an effective stimulus (monetary or physical), you have to hit hard enough and fast enough to have a noticeable effect. Since the first stimulus bill was a government programs package, rather than an actual stimulus bill, very little of the money has been used yet, so no stimulus has occurred, nor is one likely to.