there are quite a few things to do:
and now... if Tue reads this, he can do it and say "Wow, I have so good ideas!" even they're not his own. 😁
But most of those things you suggest every company should be doing. Every company could do more marketing - I notice, for example, B&O now spend a lot of money on social media, through Google AdWords etc. B&O's marketing budget is probably stretched as it is. I know our company AdWords budget and it runs in to a five figure sum. A couple of magazine adverts can cost you £5000. B&O has to market across many territories and when their sales are on the decline, the marketing budget takes a tumble.
As for celebrity endorsement. Who, exactly? You get Dr Dre on board and it might alienate your existing customerbase. You get Sir Terry Wogan on board and it might alienate a potential younger audience. Not great examples, I know, but you catch my drift.
You say "increase buying experience" and "(re)create a positive image of the brand", but these are just generic references with no indication of how they achieve this. Anyone can say "more marketing", but actioning this correctly is why the CEO is paid the big bucks.
Basically most of the above suggests require a) far more cash to be made available and b) for B&O to police their brand/stores, which requires additional staff....at the same time as they are spending cash expanding out to the Chinese and other markets.
It's an incredibly difficult balance to improve an experience and make sure you have the cash to be able to balance the books.