I agree in principle that we should try and improve posts where it is obvious what the OP is asking for, and the edit clearly improves, but does not change the nature of the question.
Where that is not possible - for example when it is not clear what the question is asking, or the question appears to be nonsensical - close votes are a valid mechanism to improve those bad posts.
In this case, none of the three sentences (including the final sentence which asks the question) or the question title were grammatical, making it actually really hard to see what was being asked. There's also no indication as to what other research the OP has done to solve their problem, nor context as to where the quoted passage comes from, making it not only a question that's difficult to understand, but also a generally bad quality question too.
With regards to your statement:
I find it hard to believe that ELL users with sufficient rep to downvote or closevote should really have any problem understanding that original text. The title makes it clear the OP is asking about meaning, not verb tense. And the last line makes it clear he wants to use the verb to cost to mean to consume.
Firstly, I didn't have any idea what the OP was asking for. That's why I eventually chose to close the question as Not a Real Question.
Secondly the first commenter on the post (WendiKidd) also explicitly states that she didn't understand the question:
I'm sorry, but I don't really understand your question. Can you give us a little more context, or perhaps make it more clear what you're asking so we can give you a good answer? I don't see the word 'consumed' anywhere else in the sentence, so 'costed' can't refer to it; therefore I'm not really sure what you mean. I will say this: in your second sentence, it should say cost, not costed. - WendiKidd
Thirdly the second commenter (jwpat7) apparently got the wrong end of the stick too. From his answer, it looks like he, like me, read the question thus:
I have found this sentence which contains a word I don't understand:
working with these steps costed much time, but they were worthwhile to get a good outcome.
I think the word costed might mean consumed, but I am not sure. Does it mean that?
To which a valid response is:
You can look up the word costed in a dictionary (which is off-topic)
The word costed in that sentence is ungrammatical, so the whole premise of the question is wrong (you should be asking what the word cost means) - i.e. the question is Not A Real Question.
This is clear by his comment which he answers by stating the definition of costed and then telling the OP that the sentence he's reading it from is wrong, and should be using cost instead.
Also see wiktionary's usage note for costed: «The only non-proscribed use is in the sense of “to give a cost to”. Where proper grammar is expected, use cost instead for non-specialized past-tense and past-participle uses such as answering the question “How much did it cost?”» – jwpat7
Indeed, even the third comment on the post - your own - can be read in such a way that it sounds like a scathing criticism of the quality of the post - although I'm not sure in hindsight that you meant it this way.
@jwpat7: That's now three of us who've all posted links to different sites making the same point about "costed". The grammar obviously bothers us at least as much as OP's actual question (is the meaning okay?). – FumbleFingers 1 hour ago edit
Which I (mistakenly) read as:
Three of us have pointed out that your grammar is wrong.
The grammar obviously bothers us.
We are also bothered by your question itself.
This was the point at which I first read the question. The question was sitting there as -1/+0 with three comments which from my perspective were pretty unanimous in their dislike for the question (although in retrospect I think I completely misread your comment), and given the poorness of the question at the time, I posted my comment suggesting that the post needed to be rewritten to be a good quality question, because several people (including myself) were unclear what the question was actually asking.
Normally with such questions, I'd just rewrite them to be better, but as someone who didn't know what the OP was actually asking for, I felt unable to do so in this case. The question looked poor, and from where I was sitting, three other people seemed to think the question was poor or misconceived too.
20 minutes later, the question now having gathered an additional 2 downvotes (now sitting at -3/+0) and having seen no change to the question itself - I voted to close the question as Not a Real Question in a last-ditch attempt to encourage the author to correct the question.
All I can say is that my tactic worked. The question has now since been edited (by you) into a question that now makes sense. All of the downvotes have been removed, the post has been reopened, gathered positive votes and now your post is a better answer to the newly devised question.