It's not that it's 'unreasonable'. It's that for most people eating out is a rare treat and if you have to deal with long waits and a lack of atmosphere due to reduced number of diners and masked up waiters, then many will simply decide that it's not worth the cost or the bother. Particularly given that a lot of people are going to be a lot less well-off in the coming months.
Plus, as I said above, most restaurants operate on very slim margins and need a full house at least at weekends in order to get by. If they have to reduce their covers by maybe 50%, in many cases it just won't be worth their while to stay open.
That's the crux of it though isn't it, if places do reopen, sooner rather than later, then there will probably need to be measures in place that minimise risk. If people find those measures are ruining the experience, then they won't come as you say. If people don't come then places close again. Vicious circle really.
But as I said in a PP, I think demand will come back at some point, and places that have been closed will reopen maybe under different management etc to meet that demand.
I guess many businesses will try and struggle on and scrape by, and succeed where others will not see the point in trying and not reopen at all.
The general lack of disposable income of course will also have an effect too. I think even if we were allowed to reopen tomorrow with no restrictions, just as it were before, we'd have a busy couple of weeks maybe and then it'd die off because people will not be able justify spending the money.
Most places do already operate on slim margins, and loss not only of footfall when reopened, but also of these busy summer months, where the money is made to see them through traditional quiet months, will have an impact on the future of a business too.
I'd like to think that some would go with it, and some places work very hard to provide an experience still so that people can relax and enjoy themselves, places can stay open and be there still when things do finally return to normal.
Maybe I'm being too optimistic because I miss my job and really do want to return. I would love to to and work a wedding right now and have 6 deep at the bar of people enjoying themselves. I just hope it's not too long before that type of thing can happen again. But to get there is going to be an uncertain and different way for everyone.