But closing of borders doesn't have to mean no entry, it can - and likely will - just mean quarantining. Any people coming in from an area where the virus is still rampant will need to be quarantined for a period of time (a couple of weeks is I think what China is using) to ensure they are virus-free when they enter. For goods/produce coming in from abroad, there will likely be strict decontamination procedures.
this is the proposed plan.
so to put it into example.
if your thinking of go from UK to disneyland paris and fee you will be free to walk around and mingle and join the queues to go on the rides... FORGET IT
however if you want an all inclusive holiday staying on the compound of a hotel. maybe
but generally dont expect to be able to go abroad and roam free for a 2 week vacation
so dont hope for much tourism unless hotels start to provide 'lock-in all inclusive' holiday packages
many sports like football(soccer) are planning to instead of having international game where people dot about into different places each day. they do all european football matches in one country where the football players stay in the neighbouring hotel for the duration of the season. to avoid racing around different countries
yep as far back as 2012 they planned to have 12 nations hosting euro 2020 but now the plan seems to be more likely to be one nation hosting all matches