"buy your software and have it forever" was not really true other than in the very early days. everything that was in active development like office, photoshop, all the pro music software i used, was updated regularly and had an upgrade cost. my music app had a paid upgrade every year like clockwork for $150. it was essentially a subscription in all but name. yeah i could stop paying and stay with the last version forever but operating system and hardware advances would make it so those versions would stop running on newer machines eventually.