I found that the proposers of features "want everything" because they don't know what is critical - they're therefore totally unwilling to accept anything other than "the full monty". So as a senior developer you cannot propose any faster route.
As you might imagine, a lot of these ideas fell by the wayside but we had to develop them in full.
It's the XY problem. The customers tell sales they want Y, rather than stating their problem X which they think Y will solve. Sales runs breathlessly to the dev team and demands we implement Y. Now scale this up to 10 customers or 100 customers. They all have the same X but come up with independent Ys.
You see the problem immediately. Sales/marketing didn't do their job sussing out what X is and wastes dev time with Ys. And worst of all, write once, support forever. Each one off Y has to be maintained for the special snowflake customer that uses it. None of the Ys actually work well for all the customers with problem X so you end up drowning in "technical debt" spent to create them all.
If your marketing department leads the company, I've discovered the best option is to just quit. Go find a job at an engineering company.
This is why the first thing you should do as a dev when somebody tells you that they want Y feature is to ask why.
Non-developers have no clue WHAT they want, then know WHY they want it. The why is much more important to know, because the requestor has no clue how software works and imagines bad solutions.
In some cases it's just because they think that any "missing thing" might be the one that causes customers to reject the offering. So they "must" have everything. It's the lack of knowledge that's the problem and they don't feel that they're going to get more than one chance/feedback cycle to learn from.
The product managers proposing things have their reputation tied up in them so a major feature is a chance at fame for them.
It's as if everyone gets "a turn" at using the development department once in a while and they want to make the utmost of it, knowing that the instant their feature is "finished" the spotlight will be gone from them for months.
As you might imagine, a lot of these ideas fell by the wayside but we had to develop them in full.