The EU will always welcome Scotland, but it will do so as a potential Member in its own right which shares the ideals of the Union and can contribute to its development; the EU would benefit strategically but has no need to accept Scotland simply to antagonise Westminster.
The harsh reality now is that any future membership of the EU would be markedly different from that envisaged before. The EU is likely to move to greater and faster political union in the next 5-10 years- its Members simply have nowhere else to turn- and that will increasingly require nations to conform to Brussels, both economically and politically. If Scotland still wished to join, it would have to go through extremely painful changes and surrender much more of its ‘independence’.
Similarly, the post-Brexit world envisioned by those currently in control of Westminster no longer appears to exist. The United States and China are entrenching and using rhetoric that sounds eerily like that of the Cold War, and the idea that there will be international free trade and great deals to be had seems fanciful. The deepest ever depression looms, a No Deal/Bad Deal Brexit awaits, which will exacerbate the economic situation, and then a weakened U.K. will find that it needs to cut deals with much more powerful entities.
Scotland will get its share of any benefits but it will also get its share of the pain. Its people will look back wistfully to what could have been in 2014 and look forward to what might be one day, though I agree with you not any time soon. Tragically melancholic, alas, but then that’s what Scots know most and best.