Yeh, everyone is forgetting that for nearly a decade Flash/Shockwave was all we had for browser games. It's true that Adobe, as always and forever, didn't care about improving security or performance after buying Macromedia. However, even left in that perpetual sluggish state, it was all there was and it did work.
There's a lot of hate for Flash in its later years but in its early years, it literally had 0% competition and was left on its own as the only easy method of interactive webpages (although the 100% Flash based webpage was always a horrible look). Anyhow, I'm not sure how things would of turned out it Flash hadn't trailblazed all those years. Maybe those who rightfully hate Adobe should still give thanks to Macromedia.