Could you name the features the contemporary (or any) MS-Office has that are important to the average secretary and that are missing in LibreOffice?
Yup, and this essentially amounts to doing things the way that MS Office does them. The way you've already learnt to do things is the easy way, because doing things any other way first requires unlearning the way you've already learnt.
100% perfect compatability with MS products since 99% of the people you will be exchanging info and docs with use MSkype products.
Yup, and it's exceedingly difficult to get 100% compatibility with MS Office without being MS Office. (Whereas MS Office gets it for free, by definition.)
Help and assistance on the Web when you need to figure something out. Easy with MS products just Google what you are trying to do and get 100s to 1000s of sites showing examples. With the FOSS options. That only works about 10% of the time.
Yup, and there'd need to be a large user base to change this
Nope, that about covers it.
FOSS products for productivity and the desktop do not yet belong on the desktop in a corporate or government environment. They are still at least another decade away from such compatability.
About a decade away from compatibility with today's MS products. In another decade, they'll still be about a decade away. It's a moving target.