I totally agree with your outlook actually, it's been shaping up for a while now, and whether or not Sony becomes market leader, it will be a close race, a few percentages here or there, but fairly evenly split when all is said and done. That much has been obvious since Sony announced it's $500 pricetag imo.
And, of course PS3 is still succesful even if it doesn't capture a huge market domination, I would never argue otherwise. It's just the people who cling to this idea that PS3 will repeat PS2's success that bother me. Despite mounting evidence to the contrary.
To me, this gen is working out perfectly, 360 has ensured itself a long and great lineup of games for years to come, and has performed well enough that I can rest assured 95% of third party titles will make it to the system. So, my purchase of $500(cad) has paid off, and I have no worries about being stuck with a small library of games.
On the flip side, Sony is now in the position where they're going to have to really focus it's efforts on it's 1st party lineup, this is great news to me, as Sony shows great vision when choosing it's franchises, and the more money/time they spend on producing them, the more great games we'll get. When I eventually do purchase one, not only will it be an affordable BR player, but it will have a great selection of high quality 1st party titles.
If Sony had dominated this genration like last, they could've scaled back their 1st party efforts considerably, which would not benefit the consumer. Instead, we have a situation where all 1st parties have to spend ALOT of money on their franchises simply to differentiate themselves, and to me this is the ideal situation for the console market.