I used to be in Gold 3-4, but something changed, and now opponents are so strong that I've slid to silver 3. I almost always face accounts that are higher than lvl 60 and often have more than 1 million of player power.

My wife quit playing because she couldn't even get past Bronze.

I don't know what the devs did to arena, but they definitely changed the way the game decides the opposition. This is what teams in silver look like these days (and this is not even the team that is at the very bottom of the page, it's 4th from the top):

I hear you.  Around the time they announced the new 3x3 I was on the cusp of Plat Tier.   Now, I'm not a top tier player, but I just kepty pushing on.  Since then, everything has become drastically harder.  My defense is almost useless, and I struggle to stay in Gold 3 for a solid week at a time.  Another in my alliance jst said the same thing...he fell into silver.   I'll be there soon, I am sure, because I can't buy a win in arena any more.   Nothing but speed tuned nukes out there now.   Annoying to play arena and never even get to launch an attack.   And when I do, I'm always resisted, even on my max accuracy Legos.  Arena has changed drastically in just 4-6 weeks.  Some suggest more people are getting stronger as the reason.  I highly doubt that so many just sailed past me in a matter of weeks.  Again, I do not claim to be top tier, but I could progress slowly before.  There's no way  all of a sudden people just got THAT good.  Something else changed.

And it keeps changing. Bronze 4 over the last week has given me fewer and fewer options for opponents within my power range. More and more the options are fully ascended 6* teams that are a mix of the best PvP champs you can get. 

They just don't belong anywhere near this bracket, plain and simple.