Difference between career graph of core jobs vs IT jobs - Can anyone share a long term view?

Depends upon what'd be "long term" (If you want really really long term view, tag #-Link-Snipped-# sir ? ). Here's my $0.02 -

I don't think there are defined career graphs these days. I've friends working in core engineering companies - designing boilers, machines and many who're in IT - writing software, creating tests, working in networking and so on. 

Also, making money is a totally different question and it doesn't have a direct relationship with the career graph. It'd be safe to assume that as you make progress in your career, your earnings go up; but not in linear fashion always. 

For Core Engineering Careers - my friends have been in technical and senior technical roles. Their work evolved from assisting senior engineers on various design and fabrication projects to being in-charge of those. They get paid "decent", but nothing extra-ordinary or out of the world. I'd say the pay they get is at par with the IT industry; but as I said - the pay depends upon several factors and there can't be a comparison without the median data across job profiles. 

for IT Careers - the career growth involves writing smaller modules / tests to leading a team and still doing technical work and then getting promoted to team management and project management roles. 

But I can tell you for sure that none of them are actually content with their jobs. Most of them are looking for change of roles or organizations for better salaries. Some are looking for executive MBA programs as they open up an extra opportunity to find a job in a totally different, non-technical profile. 

How should one decide on the career path?

You can't; unless you are absolutely sure what you want. For most of the people, the answer is "money". If someone is jobless, their first priority should be to find a job that pays them for trading their skills and time. 

Then, I think the next task is to keep finding a good job and company that you really love working for - and then continue to excel in it. That's the only, sure-shot way of making good money in the longer run. 

If someone's sure of remaining in the technical domain; they should aim to build expertise in their domain - because that'll ensure their growth in the organization. 

I hope this answer makes sense.