I agree they were always going to try it, but the point is prioritization. All the sanctions did is bump it up on the prioritization list alot. So for instance in 2011 we passed an act banning China from the ISS. The argument was that they had nothing to offer, and implicitly that they'd just steal everything. 10 years later they've created, launched and manned their own space station, have carried out the only sample return from the Moon since 1972, and in general have one of the most advanced space programs on the planet.

Had we continued to collaborate with China in space, it's likely that most of these developments would have happened at a much slower pace, simply because they'd have had a lower overall priority. Sanctions, in general, are just a very poor weapon that increasingly obviously seem at least as likely to hurt the sanctioner as the sanctioned.