There are no stablecoins out there, which we can trust 100%. Earlier I used to trust Tether, but later it was proven that they didn't backed up their tokens 100%. Bitfinex used funds from the Tether backup to cover its own losses. That makes you wonder whether any of these stablecoins are reliable. Now the Tether market cap has zoomed past the $4 billion mark. And to this date, they haven't completed external audit from any of the reliable third party vendors.
There are other stablecoins out there such as USDC, TUSD, GUSD and PAX. But after the bad experience we had from Tether, how is it possible to trust these coins? And one more thing. A recent analysis revealed that more than 80% of all the Tether tokens are being stored in just 318 addresses. This should rise enough eyebrows in my opinion. There is no other cryptocurrency out there, which has such a skewed distribution. Not even Ripple, which is regarded as the most centralized crypto.
I totally agree with your perspective. It is true not only for stable coins, for Tether USD in particular, but it is true for other things in our lives, especially in crypto market. If biggest exchanges like Poloniex, Bittrex can tail off and lose their market significantly within short period; it is possible to see Tether USD lose its position as the biggest stable coin in the future. Tether USD recently has upgrade or tried to bring more convenience to users, by switching partially to TRON, Ethereum network, rather than sticking with OMNI as it originally built. It's a good move, but not a guarentee for Tether USD's future growth.