Most don't extend employment offers out for months in my experience, or at least they really try to get you to agree off the bat. I imagine someone job searching is getting an interview once a week or so. Several times, I've had delays of weeks to months after just submitting an application to get the interview. So how do you just have multiple offers to juggle at any one time?
For my part, I have hundreds of other candidates to choose from.
People like you are the ones who grumble that it's hard to find good employees, or have to deal with "bad hires". I've built up and staffed teams for a long time and I understand that the best employees sometimes need flexibility. Because the good ones are all going and working for people who want to treat them like adults and understand that the person doing the hiring is just as disposable as the people attempting to be hired.
If timelines don't line up, you just say they don't line up and go your separate ways. No harm no foul.