Developers do as they please. Sometime it's worth listening to users, sometimes it's not. Users don't tend to know what they want until they see it - they're better at telling you what they don't want. And of course some users want things that few others do.
Personally, I would really like the 're-open closed tabs' function back. I don't use the sidebar - I have multiple screens, so it's not a case of butting up against the side of the screen, but hovering in the middle of nowhere, plus I have no interest in Instagram, Twitter, Messenger or any of the rest of the things that populate the sidebar. And I definitely don't want to permanently give up a strip of my screen for those things. But I know Instagram, etc are popular, so maybe people like the sidebar. I don't know and have no way of knowing.
I don't like searching in tabs by typing. I find that awkward - I navigate to an icon with the mouse, then take my hand off the mouse to type, then put my hand back on the mouse. Yeuch.
The icon for closed tabs went missing a couple of versions back and we've been able to work around it for a while with flags, but since version 70 (I think) the flag's gone and we can't use it at all. Given that this change has gone through the dev version and the beta version, it's unlikely it's coming back. Sigh. It was one of my favourite features of Opera and will greatly impact the utility of using it for me. It's enough of a personal favourite that I'd ditch Opera in a heartbeat to go to another browser that has it. And I've been using Opera since the mid-90s and have even paid for it in the past. But things are not designed for me personally, so if the devs want it gone, then it's gone.
What I don't appreciate is having a moderator who doesn't know the devs or have any contact with them, come in to post their own conjecture and speculation about what is going on - that isn't helpful. Leocg - you're a moderator and seen as the face of Opera. We have no means of contacting themselves or getting them to tell us anything. You're the guy who stands before us. If you have you own opinions on this, either post them as an ordinary user or keep them to yourself. Coming from your moderator account, they sound like official responses from Opera. I know you've just some volunteer who knows nothing more than any of us, but realise that the people coming here don't know that. You're not abusive, but goodness I find you rude - and I suspect you don't even realise it.