Nandalot
Yes, as a remainer I find the economic effects of the Brexit process to be alarming and depressing but I value other elements of the European community equally: its protection of human rights, ( or red tape as some leavers would probably call it); its investment in cultural and educational projects ( which I fear a national government might let go by the wayside); grants to science; collaborative projects like Galileo. I value standing together with others so that we can tackle problems together and support the weak. I do not think you can rely on America as an ally. Look how Trump is treating Canada.
With reference to your points on collaboration, the U.K. Have always collaborated both academically and technologically with other European and indeed worldwide countries, Concorde was started collaboratively well before we joined the EU for just one instance.
We will still continue to support European countries if required, just think about the two world wars, did we need the EU to stand up against tyranny? Weren't we the strongest force against this when other European countries were lacking? If you look at recent history, actually the EU has rarely stood as one to support injustices throughout the world the UK has relied on NATO partners in these matters (rightly or wrongly).
The majority of Human Rights laws adopted by the EU were derived from UK policies fought for by our unions and on the whole we still are the best within the union in their application.
Despite naysayers, the U.K. does have a good reputation in the wider world. If you travel you will nearly always find people asking how to get to UK, see building projects developed and built by UK industry, international schools staffed mainly with Brits, UK shops and goods, the list can go on. We should be developing international relationships without the constraints of 26 or 27 other countries deciding if this can be done.
I have this analogy:
Trading in the EU is like going to a furniture shop and seeing a lovely 3piece suite that you would like to buy. Before you can do this you have to ask permission from all the neighbours in your street even though they have different tastes in furnishing and decor to you, if you are very lucky you might get it or they may decide collectively that your next door neighbor should buy it.