Stablecoins are not a solution to anything. They are only there so we wouldn't have to go to fiat but that doesn't change the fact that people who move to stablecoins drop the price just like people who move to fiat. Hell if anything it helped the bear market because people can move out of crypto into stablecoins a lot more easier than fiat so people sell with a lot more ease. That is why I think it is not a solution to anything, it wasn't needed and shouldn't exist but since it exists already right now there is nothing we can do to remove them from the ecosystem anymore, if you get rid of one of them (which tether is getting removed over time) another one will take its place.
It is a sad cycle we will have to endure and be patient about so that with time we can find the mean average of it.
While stablecoins prove to be extremely convenient to protect your investment against price volatility, it has been the perfect tool for market manipulation. This of course, has led us to a bear market along with a wave of regulations imposed by governments worldwide. The way crypto has been heading since it came into inception has been towards centralization than anything else. After all, mainstream businesses and companies have taken the lead over most crypto services, resulting in a lower level of decentralization over time. Depending on the person's point of view, stablecoins are either benevolent or malevolent to the entire crypto industry.
Personally, I'd use stablecoins to serve as a "hedge" between the worlds of crypto and Fiat. The only downside is that most (if not all) stablecoins are prone to have a slightly lower price than $1 USD per coin at times. We've seen how Tether went from being worth $1 per coin to $0.98 (and sometimes a little lower), which is something a serious trader or investor would find hard to deal with. Not to mention, NuBits (USNBT) used to be a stablecoin with a value of $1 USD per coin only to fail a couple of years later. With proper regulation from worldwide governments, we might be able to see major stablecoins retain their value of $1 USD per coin for the foreseeable future.
Nonetheless, I believe that at some point, stablecoins are an ideal solution for a bear market. But they're not a "definite" solution, as there are other ways which you can secure your investment against crypto's volatility on the market. You'd either convert your crypto into physical cash or a stablecoin of your choice to protect yourself against any bear market. Depending on your needs, will be the type of currency to choose. In the end, stablecoins will survive as people in the mainstream world find them as an attractive alternative to the traditional US Dollar of today. Just my thoughts