Airbags are an extremely important piece of modern car safety equipment and will continue to be used for as long as there are cars. The most recent airbags and those yet to be developed must offer improved levels of safety with reduced disadvantages.
One way of doing this is to do remove the sodium azide propellant and replace it with another source of gas. Some modern airbags have reverted to the original technology of using a canister of compressed gas such as argon. Modern science now permits these canisters to be much more reliable than when they were first introduced back in the 1950s. The so-called hybrid devices are detonated by rapid heating of the argon by a small amount of propellant, the canister then bursts open releasing the gas into the airbag. At the moment these devices are much less compact that the traditional ones and so aren't small enough to be used in the steering wheel but are extensively used for the passenger and side airbags where there is more room to mount them.