Schengen - Who benefits?

The traveller benefits; you get access to visit all the signatory member countries during that 90 days, be it for business or pleasure, otherwise you would need to apply for individual visas.

@Cynic ok, but why restrict it to 90 days. Why not 6 months or longer?

    @Cynic ok, but why restrict it to 90 days. Why not 6 months or longer?
   

    -@Rob Hall2

How long can I stay with a tourist visa in the USA? 6 months? As long as I like?

    @Cynic ok, but why restrict it to 90 days. Why not 6 months or longer?
   

    -@Rob Hall2

They have other visas for that.

@Rob Hall2

Everybody agrees that getting a visa is a pain in the proverbial, and most countries don't want to put up unnecessary barriers to foreigners popping over to spend money on vacations, sightseeing and business trips. Therefore, most countries allow some kind of visa-free regime for the reasons you suggest. This is extended (usually) to most wealthier countries, but excludes a number of poorer countries. (On the basis that wealthier countries tend to have wealthier citizens who tend to come for tourism and business while poorer countries tend to have poorer citizens who tend to be economic migrants seeking to work and overstay.)

The most common visa-free period is 90 days, but there are shorter (e.g. 30 days, Philippines) and longer (e.g. 180 days, UK).

In my experience, all folks on the visa-free list are treated identically and admitted for the period allowed. I've not seen any countries which allow some countries on the list (such as Americans) an even longer period, because they're such nice folks, and they spend so much when they travel. :-)

Many countries (e.g. Panama, UK) don't formally require a departure period before returning. This is the "visa run" where someone flies/drives/sails out, then pops back in shortly after. Even if a gap is not strictly required, immigration officials will normally look carefully at people doing fast out/ins or repeated out/ins, and might even choose to exclude them. (On the basis that it appears that you're living there, rather than being a typical tourist. Immigration officials can kinda do what they want, the visa-free allowance is a privilege NOT a right,) The Schengen Zone (and it's the same rule for individual EU countries) formalizes the gap, by having the up to 90 days in 180 days rule. If you're not living there, it's not an issue. And I think it makes the rules quite clear, so you can be confident that you CAN return before you spend money booking flights and hotels.

For comparison, the USA has the Visa Waiver Program combined with ESTA (system for PRIOR travel approval) which allows 90 days. (Schengen/EU is about to introduce something similar, ETIAS.)

I don't think the USA has a minimum period before returning, but there are some murky rules over the exact out/in method, and very aggressive border control officials who will almost certainly raise detailed questions of any TCN who makes immediate returns, or multiple visits with little or no break.

If you want to stay longer than 90 days, many countries have some form of residence visa which is for non-workers and easier to get (e.g. No Lucrativa Visa in Spain, D7 in Portugal). And, in general, it's MUCH easier to get such a visa than the equivalent process for us foreigners stay in USA (which I don't think even has a non-working residence visa of the type mentioned).

Just like America, the EU is a relatively wealthy bloc of countries, and hence an attractive destination for many TCN economic migrants. Just like America, the EU (and Schengen) have tried to implement robust border controls to try to restrict these flows into the EU. Schengen is an attempt to remove this border friction once you've entered the EU, but want to travel to another EU country. This is similar to how America is hard to get into... but once you've been admitted, there's no aggravation if you want to drive from California to Nevada to Utah.

a friend of mine said this "It's basically a revolving door policy that restricts tourism in a effort to prevent tourists from overrunning the locals.  Thats what I was looking for.  In fact, when I googled "overrun" the 1st definition is:

spread over or occupy (a place) in large numbers.

"the Mediterranean has been overrun by tourists"

It is a calculation that 3 months at a time is enough for legitimate tourism. Allowing longer times expands peoples’ opportunity to try and illegal stay and work. And the fact is that most people from advanced countries that have lots of money to travel have limited time for vacations.  Most working Americans for example only get a few weeks a year. I can imagine that there are people with legitimate interests to stay longer but not a significant number to make it worth the downsides of changing the policies. And most of Europe is not hurting for tourists.

@Rob Hall2

He may have said that, but it really doesn't make sense. One of the main objectives of visa-free policies is specifically to promote tourism by reducing the friction of travelling to a particular country. And, indeed, almost every country (including Spain) welcomes tourism and the boost to the local economy that results from tourists and their money. If Spain didn't have visa-free travel, maybe 90% of summer visitors would find a nice beach in Italy, Cyprus, Greece or Turkey to go to instead!

It may be true that some places (e.g. Barcelona, Venice, "the Mediterranean") are arguably "overrun" by tourists, but it's very subjective: many folks in those locations are very happy to take your money, and would like to take even more. There's very little consensus on what constitutes overtourism or what to do about it. Certainly a country-level visa-free tweak is not an appropriate policy mechanism when you want to address a localized problem. Indeed, many places want to keep up tourism numbers (or even increase it), but generate extra revenue from various forms of tourist taxes.

Spain is a bad example, because most tourists are from EU/Schengen countries and do not need visa anyway. The 90 in 180 rule only applies to non-EU travellers and for tourists this should be ample.