Shinkansen related questions

Because i am bored and because all the fastest shinkansen trains that i have used on my trips are kind of full :-)
1. Are the tracks for Tohoku and Tokaido shinkansen connected? I.e is it possible for a shinkansen train due maintenance etc reasons to go from Shinagawa to Omiya using railway tracks?
2. Who are the main users of the shinkansen? Ordinary persons who pay for the ticket themselves or company customers (company pays for the tickets and in the end the customer of the company products-services pays for it).
3. If business persons - what is the main reason they travel a la from Tokyo to Osaka? Is it sales (i.e visiting customers), technical persons (who fix/repair something) or something else.
4. Is it possible for the business entity with good reputation to receive one single invoice regarding train travel from the JR group so the workers only have to do the reservation process but not handle the payment?
5. Is it a valid comparison: in Europe low wage person is using either public transportation or VW Golf or other small and cheap car for commuting from home to work and rich person is using Audi A8 or S class Mercedes, but in Japan for example between Takasaki and Tokyo a low wage worker is using local train but middle class or rich person is using shinkansen?

BR,
Lauri

1: No. As far as I know the tracks terminate at Tokyo station and are not connected. Might be why there are two "Dr Yellow".

2: Ordinary people are the main users. Still lots of company travel and a long way back are tourists from over-seas.

3: Why do business people travel by train/air in other countries? Same reasons in Japan - sales/client meetings, deal with staff, attend conferences, all sorts.

4. They could use one of the JR travel companies, like using a travel agent, so yes.

5. No.

JapanCustomTours, thank you for the answers.

As i have understood - because car for generic use is pretty expensive in Japan (compared to Europe or US), specially if you live between the heavily populated Tokyo-Hiroshima line, then it is probably more cost effective for all kind of specialists to travel with public transportation instead of a car assuming you do not have to carry heavy stuff?
As an IT support person i have never travelled to the customer site in my country with a public transport, because the TCO is much better with a car in Estonia.
That was my meaning of the question about the shinkansen usage statistics i.e who are the main users and whether in the grand scheme of things the shinkansen network is meant for the consumers (tourists, people commuting to work) or for business users (sales, finance, technical stuff - to improve the economy in general).
Are IT persons (who set up network equipment, servers, do administrative work etc.) and high end doctors (for example those who mainly work in Tokyo, but perform sometimes difficult surgeries in Osaka hospitals) also called "salarymen"?

Dr. Yellow is for JR Tokai and Easti is for JR East. Each of those two JR companies have their own diagnostics train. I don't think an N700 would ever need to be serviced at Omiya, since that is JR East and they don't service that type of trainset.

@John - thanks - interesting about the JREast diagnostics train - an E3 - I had not checked what type they were using.

You are welcome....happened to catch it on video once speeding by Utsunomiya Station about 5 years ago.

The power systems for overhead supply are also different. Making each other incompatable noeth and south of Tokyo. 50 vs 60Hz.

The newer E7s/W7s have the ability to accept both frequencies.