To suggest that MS are on a 'slide' because they're products are adequate rather than exceptional is wrong because they suit the vast majority of people's needs. MS will lose market share but they will still dominate because of market entrenchment.
Kind of like VHS tapes and plastic records were entrenched ...?
And as to 'adequate is ok' ... sheesh .. have you not realized that is why MS is sliding, sorry Apple is climbing? Apple users 'LOVE' the products because they are 'insanely great'. PC users often see a Mac in use by a friends and say "I have got to get one of those!' Tell me how many Mac users watch a PC user and say 'Wow, I have got to have that, it is so adequate!".