The next recession is inevitable, if what I read is to be believed. Whether it happens tomorrow, or in 10 years, it's coming. Why shouldn't I short many stocks, and hold on to them for whatever amount of time is necessary to make the trades profitable?
The margin requirement under Regulation T for shorting stock is 50% of the value of the shares. The minimum margin maintenance requirement is 125% of the current market value of the short sale. Some brokers have higher requirements.
Yes, the next recession is inevitable but when it occurs can make or break your proposed strategy. The more the share price of your short positions rise, the larger the margin requirement will become. If the stocks keep rising, at some point you will have get a margin call and you will have to add more cash to your account. As John Maynard Keynes once said, "The market can remain irrational longer than you can remain solvent."
A secondary problem is that there is a borrow cost paid to the lender of the shares. Liquid large caps stocks can have a borrow rate of as low as .25% per year but more volatile stocks which are more likely to drop more and faster have larger borrow rates. The really crazy stuff can have borrow rates over 100% per year.
If the inevitable recession occurs in 10 years then "Houston, we have a problem!"
Save the shorting for when the recession begins. The bear markets of 2000 and 2008 took 18 months to unfold. React, don't predict.