Absolutely. It will happen in the U.K. no doubt. Given that LDHS trains already stop at, or near to, a number of Airport stations, inc Heathrow, I do wonder why this hasn’t happened already though? I suspect it’s largely to do with the fact that these services are largely the flagged carriers combining with the national(ised) rail operator (eg your example of OBB/Austrian Airlines) But I think FQTV would know more about this.While I have no intention to weigh in on the merits of a through HSL to Scotland and of serving Heathrow, I just want to mention that having long-distance trains stop at major airports and offer through-ticketing so as to guarantee connections is not so rare on the continent. German Rail has done this for years and recently it is being done in Austria as well - ÖBB trains to Vienna Airport have replaced some domestic flights and carry Austrian Airlines flight numbers.
While it is not for everyone, it is a good alternative for lots of people, especially the huge „fly to XYZ for the weekend with a carry-on-bag“ crowd as well as for business travellers, who usually avoid large amounts of luggage. Pressure to reduce short-haul-flying is only going to increase.
Once HS2 and NPR reach Manchester Airport, something very similar could be established in the UK.