Assuming it's a 'proper' hardware upgrade, whether i buy it or not will depend on how they approach it. If the current PS4's technical standards remain consistent, and the new PS4 is purely a fully optional visual bump (with perhaps some exclusive PSVR titles, but little else locked away from the original), then sure, i could see myself picking one up. Certainly not right now, but eventually.
If, however, we do see a drop in the current PS4's standards, and it is lathered with traditional exclusive titles, then no, i won't be buying it. While i could half-heartedly support a mid-gen console upgrade that simply gives consumers more choice, i have no interest in supporting something that's existence punishes those not willing to throw more money at it.