That’s actually a separate issue, crises of overproduction are unique to capitalism because of “anarchistic” production.

Decreasing rate of profit is what happens with “innovation”. As you develop the means of production, you increase the productivity of a working hour at the expense of a larger capital outlay in means of production. This creates the conditions for monopoly as the only capitals able to front the money for a profitable enterprise are existing large ones.

Small firms are pushed out because the profitability of a working hour is set by the output of the large manufacturers, so as those small holders fail, their workforces go to work for the large capital for less pay even though their productive output is higher because they’re paying for the cost of the initial capital outlay with their surplus value.